ALBERT

All Library Books, journals and Electronic Records Telegrafenberg

X
feed icon rss

Your email was sent successfully. Check your inbox.

An error occurred while sending the email. Please try again.

Proceed reservation?

Export
Filter
  • American Institute of Physics (AIP)  (5,187)
  • 1985-1989  (5,187)
  • 1980-1984
  • 1986  (5,187)
  • 1
    Electronic Resource
    Electronic Resource
    Inner shell excitation of thiophene and thiolane: Gas, solid, and monolayer states (1986)
    College Park, Md. : American Institute of Physics (AIP)
    The Journal of Chemical Physics 85 (1986), S. 4835-4848 
    Details
    ISSN: 1089-7690
    Source: AIP Digital Archive
    Topics: Physics , Chemistry and Pharmacology
    Notes: The electron energy loss spectra of gaseous thiophene and thiolane in the regions of S 2p, S 2s, and C 1s are presented along with the x-ray photoelectron yield (NEXAFS) spectra of both gases in the region of S 1s excitation. The thiophene spectra are compared to the corresponding NEXAFS spectra of solid (multilayer) and monolayer thiophene on Pt (111). MS-Xα calculations of the C 1s, S 2p, and S 1s excitation spectra of free thiophene are also reported. Intercomparison of the gas, surface, and calculated spectra allows a complete interpretation of the spectral features and facilitates determination of the molecular orientation of thiophene with respect to the surface in both the compressed [thiophene on Pt (111) at 150 K] and relaxed [thiophene on Pt (111) at 180 K] monolayer phases.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.451718
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 2
    Electronic Resource
    Electronic Resource
    Vacuum ultraviolet absorption cross sections of SiH4, GeH4, Si2H6, and Si3H8 (1986)
    College Park, Md. : American Institute of Physics (AIP)
    The Journal of Chemical Physics 85 (1986), S. 4867-4872 
    Details
    ISSN: 1089-7690
    Source: AIP Digital Archive
    Topics: Physics , Chemistry and Pharmacology
    Notes: The vacuum ultraviolet absorption cross sections of SiH4, GeH4, Si2H6, and Si3H8 are reported for the wavelength region 107–220 nm using synchrotron radiation as a light source. Absorption maxima of these compounds were found at the exciting wavelengths of 115–119 nm. Broad peaks observed were mostly assigned as primarily Rydberg transitions of the σSiH and σSiSi bonding electrons to the 4s, 4p, and 4d orbitals. The absorption features of germane resemble those of monosilane. In the photoexcitation of monosilane, the emission of the SiH(A˜ 2Δ→X˜ 2Π) transition was observed and its onset was found to be 132±2nm. The absorption spectrum of disilane showed five peaks. They were mostly assigned as 2a1g→4s, 2a1g→np(n=4−6) transitions and the strongest band was overlapped by 1eg→4d and 1eu→4p Rydberg transitions. In trisilane molecules three very weak and broad peaks were recognized and assigned as 3b2→4s, 4p and 4a1→4s, 4d Rydberg transitions. The strongest band was tentatively assigned as the superposition of 1a2→4d and 3a1→4p Rydberg excitations.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.451721
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 3
    Electronic Resource
    Electronic Resource
    Carbon K-shell excitation of gaseous and condensed cyclic hydrocarbons: C3H6, C4H8, C5H8, C5H10, C6H10, C6H12, and C8H8 (1986)
    College Park, Md. : American Institute of Physics (AIP)
    The Journal of Chemical Physics 85 (1986), S. 4849-4862 
    Details
    ISSN: 1089-7690
    Source: AIP Digital Archive
    Topics: Physics , Chemistry and Pharmacology
    Notes: The carbon K-shell excitation spectra of gaseous cyclic hydrocarbons, both saturated (cyclopropane, cyclobutane, cyclopentane, cyclohexane) and unsaturated (cyclopentene, cyclohexene, and cyclooctatetraene), have been recorded by electron energy loss spectroscopy under dipole-dominated conditions. These are compared to the NEXAFS spectra of multilayers and monolayers of C4H8, C5H8, C6H12, and C8H8 on Pt(111). Multiple scattering Xα calculations of the spectra of cyclopropane, cyclobutane, and cyclohexane are also reported. In most cases the gas and solid spectra are essentially the same indicating that intramolecular transitions dominate in the condensed phase. The NEXAFS polarization dependence of the condensed phases has assisted spectral assignments and the determination of the molecular orientation in the monolayer phase. In the saturated species a sharp feature about 3 eV below the carbon 1s ionization threshold is identified as a transition to a state of mixed Rydberg/valence character with the π*(CH2) valence component dominating. Except for cyclopropane the positions of the main σ * resonances correlate with the C–C bond lengths in a manner similar to that reported previously for noncyclic aliphatic molecules. In the spectra of monolayer C6H12, C5H8, and C8H8 spectral broadening and weak additional features are observed which are attributed to molecule–surface interactions.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.451719
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 4
    Electronic Resource
    Electronic Resource
    Theory of chemical exchange in zero field NMR: Two-site flips (1986)
    College Park, Md. : American Institute of Physics (AIP)
    The Journal of Chemical Physics 85 (1986), S. 4873-4880 
    Details
    ISSN: 1089-7690
    Source: AIP Digital Archive
    Topics: Physics , Chemistry and Pharmacology
    Notes: In zero field NMR, the spectra are characterized purely by the quadrupolar or dipolar interactions, which are sensitive to molecular motion. An analytical theory is presented which describes the effect of two-site flips of a deuteron on its zero field NMR spectrum and demonstrates the potential of this novel technique in the investigation of molecular dynamics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.451722
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 5
    Electronic Resource
    Electronic Resource
    Raman spectrum of ammonia solid II (1986)
    College Park, Md. : American Institute of Physics (AIP)
    The Journal of Chemical Physics 85 (1986), S. 4903-4904 
    Details
    ISSN: 1089-7690
    Source: AIP Digital Archive
    Topics: Physics , Chemistry and Pharmacology
    Notes: Raman spectra of the orientationally disordered phase II of solid ammonia in the intramolecular and lattice regions are reported for the first time. The spectrum of the intramolecular region contains one line for each vibrational mode, broadened by the orientational disorder. The lattice region contains two broad lines near 50 and 280 cm−1, assigned to translational modes, and two central peaks ascribed to rotational relaxation.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.451725
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 6
    Electronic Resource
    Electronic Resource
    High resolution IR laser spectroscopy of van der Waals complexes in slit supersonic jets: Observation and analysis of ν1, ν1+ν2, and ν1+2ν3 in ArHF (1986)
    College Park, Md. : American Institute of Physics (AIP)
    The Journal of Chemical Physics 85 (1986), S. 4890-4902 
    Details
    ISSN: 1089-7690
    Source: AIP Digital Archive
    Topics: Physics , Chemistry and Pharmacology
    Notes: IR spectra of jet cooled ArHF are obtained via direct absorption of a high resolution tunable difference frequency laser in a 2.54 cm path length, slit supersonic pulsed expansion at 〈10 K. Detection limits of 2×109 molecules/cm3/quantum state permit observation of the high frequency ν1 fundamental stretch (1000) ← (0000), the ν1+ν2 van der Waals bend plus stretch combination band (1110) ← (0000), as well as transitions to the (1002) triply vibrationally excited state that are weakly allowed via Coriolis interactions with the Π+ component of the (1110) manifold. The ground state (0000) molecular constants are in excellent agreement with previous microwave data. From the changes in rotational and centrifugal distortion constants, the vibrationally averaged van der Waals well depth is estimated to increase (+15%) with ν1 excitation, but decrease dramatically (−42%) upon subsequent excitation of the l=1 ν2 bend. L-doubling in the ν1+ν2 (1110) perpendicular bending state is large and negative [−69.8(18) MHz] and indicates the presence of a near resonant Coriolis coupledvibration of Σ+ symmetry at lower energy. A second, localized Coriolis perturbation is observed in the (1110) state and assigned to the near resonant (1002) Σ+ fundamental plus van der Waals stretch overtone at higher energy. Analysis of this Coriolis interaction indicates that coupling can be significant even for a three quantum change in vibration. However, a perturbative, small amplitude oscillator model predicts Coriolis matrix elements only 18% of the observed values, suggesting that large amplitude, bend–stretch interactions can strongly enhance Coriolis coupling. The decrease in the B rotational constant and the vibrationally averaged well depth upon ν2 excitation confirms the strong coupling between van der Waals stretch and bend coordinates. The slit expansion geometry quenches perpendicular velocity distributions and therefore offers intrinsically sub-Doppler resolution in an unskimmed molecular beam. Residual linewidths in the ArHF spectra are all below the apparatus resolution limit of ±25 MHz, which translates into a lower limit for the predissociation lifetime of 3 ns, i.e., in excess of 2×106 ν1 vibrational periods.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.451724
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 7
    Electronic Resource
    Electronic Resource
    Quantitative spectroscopy study of HBr in the 105–235 nm region (1986)
    College Park, Md. : American Institute of Physics (AIP)
    The Journal of Chemical Physics 85 (1986), S. 4919-4924 
    Details
    ISSN: 1089-7690
    Source: AIP Digital Archive
    Topics: Physics , Chemistry and Pharmacology
    Notes: The photoabsorption and fluorescence cross sections of HBr were measured in the 105–235 nm region using synchrotron radiation as a light source. Sharp absorption bands were observed in the 105–120 nm region. These bands were classified into Rydberg series, and their oscillator strengths were measured. Fluorescence in the ultraviolet region was observed and used to identify the V 1∑+ state.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.451728
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 8
    Electronic Resource
    Electronic Resource
    Observation of anomalous pulse duration dependent IR absorption spectrum in C3F7I (1986)
    College Park, Md. : American Institute of Physics (AIP)
    The Journal of Chemical Physics 85 (1986), S. 4912-4918 
    Details
    ISSN: 1089-7690
    Source: AIP Digital Archive
    Topics: Physics , Chemistry and Pharmacology
    Notes: The collisionless infrared absorption spectrum of C3F7I was measured with picosecond and nanosecond CO2 laser pulses. The spectral width was found to decrease significantly as the measuring pulse duration was reduced. This data was interpreted with the multitier level scheme of the vibrational quasicontinuum. It was concluded that the measured absorption spectrum for any polyatomic molecule in a dense vibrational quasicontinuum should be dynamic in general and should depend on the interaction time. This is because the number of states interacting with the laser field indirectly via intramolecular coupling is time dependent. Therefore, the essentially static spectral measurement can yield dynamical information on the interaction of energy levels within the molecule.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.451727
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 9
    Electronic Resource
    Electronic Resource
    Pressure effects on the far infrared spectra of dimers, trimers, and aggregates of HCl molecules trapped in Ar and Kr matrices at 4.2 K (1986)
    College Park, Md. : American Institute of Physics (AIP)
    The Journal of Chemical Physics 85 (1986), S. 4925-4931 
    Details
    ISSN: 1089-7690
    Source: AIP Digital Archive
    Topics: Physics , Chemistry and Pharmacology
    Notes: By slowly cooling under pressure diluted solutions of HCl molecules in argon or krypton we have obtained different aggregation states of these molecules: dimers, trimers, and even aggregates and microcrystals. Thick solid samples (up to 14 mm) have been cooled down to 4.2 K and compressed within the range 0–5 kbar using a piston–cylinder device. The new spectroscopic data on dimers and trimers, in connection with some results previously obtained at low pressure in various matrices, lead us to confirm that the band frequencies of dimers and trimers are mainly sensitive to the intermolecular separation and do not appreciably depend on the nature of the rare gas matrix. The HCl aggregates are clearly distinguished from the microcrystals because of the quite distinct behavior observed for their corresponding translational modes. Finally, emphasis is made on the first observation of an unexpected and strong absorption band, centered at 200 cm−1, which disappears irreversibly under the effect of pressure. Its possible origin is discussed and tentatively ascribed to structure defects.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.451729
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 10
    Electronic Resource
    Electronic Resource
    A paramagnetic Cl–O defect produced by x irradiation of KBr:ClO−4 (1986)
    College Park, Md. : American Institute of Physics (AIP)
    The Journal of Chemical Physics 85 (1986), S. 4938-4942 
    Details
    ISSN: 1089-7690
    Source: AIP Digital Archive
    Topics: Physics , Chemistry and Pharmacology
    Notes: Experimental results on KBr@B:ClO−4 single crystals, before and after x irradiation at 77 K, are reported. Infrared and polarized Raman spectra show clearly that the perchlorate molecules are isolated in the KBr matrix and possess Td symmetry. EPR spectra, at 9.5 and 36 GHz, of irradiated crystals at 4.2 K indicate the formation of ClO2−4 in trigonal symmetry. The g and 35Cl hyperfine tensors are found to be strictly axial and collinear. Temperature variation of the EPR spectra presented no motional averaging while uniaxial stress applied to the crystals yielded negative results. The structure of the ClO2−4 molecule is discussed in terms of a trigonal Jahn–Teller effect and a probable dissociation into (ClO−3–O−) complex.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.451731
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 11
    Electronic Resource
    Electronic Resource
    Spin-orbit interactions and dynamical Jahn–Teller effect in the 4E states of Mn2+ in cubic and nearly cubic symmetry (1986)
    College Park, Md. : American Institute of Physics (AIP)
    The Journal of Chemical Physics 85 (1986), S. 4932-4937 
    Details
    ISSN: 1089-7690
    Source: AIP Digital Archive
    Topics: Physics , Chemistry and Pharmacology
    Notes: A very detailed analysis of the fine structure of the 4E(G) state of Mn2+ in cubic and nearly cubic clusters is presented to account for the unusual fine structure observed in ZnSe:Mn. First, experimental results are reported which show that the spin-orbit interaction in the 4E(G) state of Mn2+ in ZnSe is about one half of that previously observed in cubic or nearly cubic clusters as MnS4, MnBr4, and MnCl4 and that the state Γ8 is neatly shifted with respect to the Kramers doublets Γ6 and Γ7. Second, a model is elaborated which shows that second-order spin-orbit interactions reduced by a Jahn–Teller coupling to E vibrational modes accounts well for the observed overall splitting of the 4E(G) state in the studied clusters and that fourth-order spin-orbit interactions correctly describe the shifts of the Γ8 state. The validity of the perturbation schemes is discussed and the results are compared to those obtained from a complete diagonalization in the d5 configuration.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.451730
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 12
    Electronic Resource
    Electronic Resource
    Triplet Rydberg states in molecular nitrogen (1986)
    College Park, Md. : American Institute of Physics (AIP)
    The Journal of Chemical Physics 85 (1986), S. 4943-4948 
    Details
    ISSN: 1089-7690
    Source: AIP Digital Archive
    Topics: Physics , Chemistry and Pharmacology
    Notes: A pulsed electric discharge in a pulsed supersonic jet of N2 is found to produce high densities of metastable E3Σ+gN2. Subsequent laser irradiation of these metastables results in single-photon excitation to autoionizing states. Singly charged cations are detected by time-of-flight mass spectrometry or alternatively, ejected electrons are detected by TOF electron energy analysis. From both the laser excitation spectra and photoelectron spectra we have identified a number of autoionizing Rydberg states, including a triplet Rydberg series (np=8−26) 3Πu←E 3Σ+g converging to the ground state ion, the first member of an s-type triplet Rydberg series 3Σ+u←E converging to the B state of the ion and the lowest member of a d-type triplet Rydberg series 3Πu and 3Σ+u←E converging to the A state of the ion. Some of these transitions involve core excitations of a 3s Rydberg state configuration, resulting in a doubly excited electronic configuration [He(2sσg)2(2sσu)(2pπu)4 (2pσg)2(3sσg)]. Other transitions confirm that the E state is a mixture of a 3s Rydberg state with an X ionic core and a 3p Rydberg state with an A ionic core.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.451732
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 13
    Electronic Resource
    Electronic Resource
    Decoupling of the local mode stretching vibrations of water through rotational excitation. I. Quantum mechanics (1986)
    College Park, Md. : American Institute of Physics (AIP)
    The Journal of Chemical Physics 85 (1986), S. 4949-4957 
    Details
    ISSN: 1089-7690
    Source: AIP Digital Archive
    Topics: Physics , Chemistry and Pharmacology
    Notes: We demonstrate that in a previously studied model of the stretching modes of the water molecule rotational motion in the plane of the molecule tends to decouple the stretches. For rotational angular momentum near J=18 (h-dash-bar), the two local mode stretches are almost entirely decoupled. The source of this decoupling is the centrifugal distortion which stabilizes the asymmetric stretch and effectively cancels the G-matrix coupling. This cancellation is clarified using three different methods: Direct examination of the numerically computed matrix elements, exact analytic matrix elements of an approximate Hamiltonian, and solutions of a Mathieu equation formulation of a classical resonance Hamiltonian. The importance of this result is discussed in light of the fact that strong rotational excitation can occur in infrared multiple photon excitation. If such rotational decoupling occurs in real systems, then intramolecular energy transfer would be diminished thus holding open the possibility of mode specific infrared excitation. The calculations were carried out by numerically evaluating matrix elements between a basis of Morse oscillator eigenstates using an efficient Gaussian quadrature scheme based on associated Laguerre polynomials.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.451733
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 14
    Electronic Resource
    Electronic Resource
    Intramolecular conversions over low barriers. VII. The aziridine inversion—Intrinsically non-RRKM (1986)
    College Park, Md. : American Institute of Physics (AIP)
    The Journal of Chemical Physics 85 (1986), S. 4980-4988 
    Details
    ISSN: 1089-7690
    Source: AIP Digital Archive
    Topics: Physics , Chemistry and Pharmacology
    Notes: The rate of bond inversion at the nitrogen atom in aziridine (dimethylene-imine) was measured in the gas phase for a range of pressures and temperatures. 1H NMR spectra were recorded of samples at 5–1100 Torr, and from 298 to 388 K. Rate constants for inversion were derived by complete line shape analysis of the NMR spectra. Their temperature dependence at the high pressure limit (1100 Torr) gave Ea =15.8±0.4 kcal mol−1; ΔH
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.451712
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 15
    Electronic Resource
    Electronic Resource
    Higher-order moments in macrotransport processes (1986)
    College Park, Md. : American Institute of Physics (AIP)
    The Journal of Chemical Physics 85 (1986), S. 5238-5245 
    Details
    ISSN: 1089-7690
    Source: AIP Digital Archive
    Topics: Physics , Chemistry and Pharmacology
    Notes: A novel moment-gradient expansion scheme, expressing the microscale probability density P as an infinite sum of global-space gradients of its corresponding macroscale density P¯ multiplied by coefficients formed from its local and total moments, is employed to derive an asymptotic long-time macrotransport equation from its more detailed microtransport predecessor. Particular emphasis is paid to third- and higher-order gradient terms in the expansion. These are shown to result in non-Gaussian behavior of the macroscale probability density P¯ governing convective–diffusive transport processes.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.451664
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 16
    Electronic Resource
    Electronic Resource
    Molecular dynamics study of a dipolar fluid between charged plates (1986)
    College Park, Md. : American Institute of Physics (AIP)
    The Journal of Chemical Physics 85 (1986), S. 5232-5237 
    Details
    ISSN: 1089-7690
    Source: AIP Digital Archive
    Topics: Physics , Chemistry and Pharmacology
    Notes: Recent experiments and computer simulations of thin films have observed the segregation of nonpolar molecules into layers or sheets parallel to the confining walls. We discuss a molecular dynamics study of a thin film of Stockmayer molecules between Lennard-Jones plates and find that, in the absence of an electric field, the dipoles are mainly oriented parallel to the plates in each layer. The component of the dipole autocorrelation function in this plane decays to zero more slowly than the component perpendicular to the walls. The polarization density profile, with an electric field perpendicular to the plates, is also studied, and is found to oscillate from layer to layer, with a magnitude that is in excess of what is predicted by the Debye theory of dielectric saturation by a factor nearly equal to the ratio of the local density to the average bulk density.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.451663
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 17
    Electronic Resource
    Electronic Resource
    Polarized and depolarized Raman spectra of liquid carbon disulfide in the pressure range 0–10 kbar. I. Vibration frequencies, C–S bond length, and Fermi resonance (1986)
    College Park, Md. : American Institute of Physics (AIP)
    The Journal of Chemical Physics 85 (1986), S. 2538-2547 
    Details
    ISSN: 1089-7690
    Source: AIP Digital Archive
    Topics: Physics , Chemistry and Pharmacology
    Notes: The effect of pressure on the polarized and depolarized Raman spectra of liquid carbon disulphide, i.e., the peak frequencies, bandwidths, and relative intensities of both the allowed ν1 and 2ν2 bands and the interaction-induced ν2 and ν3 bands, have been measured at 22 °C up to 10 kbar. This paper discusses the effect of pressure on the frequencies and on the relative isotropic intensity of the ν1 and 2ν2 bands. The frequency of the ν1 band increases linearly with pressure, within the experimental uncertainty, at the rate 0.16±0.01 cm−1 kbar−1, and the frequencies of the ν2, ν3, and 2ν2 bands decrease nonlinearly. The frequency shifts are described by second-order perturbation theory with the molecular anharmonicity and the intermolecular interaction as perturbations. The leading terms of the shifts consist of the same derivative of the interaction potential, multiplied by different anharmonicity constants, and the shifts of the ν1 and 2ν2 bands suggests that the C–S bond length decreases at the rate 2×10−4 A(ring) kbar−1. The relative isotropic intensity of the 2ν2 and ν1 bands increases with pressure at the rate 0.050 kbar−1, whereas the anisotropic 2ν2 intensity relative to the isotropic ν1 intensity is independent of pressure to the experimental precision of ∼0.005. The effect of pressure on the second derivative of the isotropic and anisotropic parts of the polarizability with respect to the bend coordinate was estimated as 1.1×10−43 C m2 V−1 kbar−1 and ∼0, respectively, from these values.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.451061
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 18
    Electronic Resource
    Electronic Resource
    Decay kinetics of the ultraviolet and visible luminescences emitted by electron-irradiated crystalline H2O ice (1986)
    College Park, Md. : American Institute of Physics (AIP)
    The Journal of Chemical Physics 85 (1986), S. 2555-2568 
    Details
    ISSN: 1089-7690
    Source: AIP Digital Archive
    Topics: Physics , Chemistry and Pharmacology
    Notes: Electron pulse irradiated samples of high purity, crystalline H2O ice at 88 K showed three kinetically distinguishable regions of luminescence emission at 280–340 nm (band I); 320–600 nm (band II); and 450–600 nm (band III). Band II emission was assigned to the A 2∑+→X 2Π transition of OH, the gas phase peak being shifted from 306.4 to ∼385 nm by the ice lattice. The decay half-life of the band II emission resulting from a single, ∼0.05 Mrad electron pulse, was 25±3 ns and increased steeply to 210±10 ns for the second pulse and then steadily decreased to 140±10 ns after 20 pulses. Band II emission from the second or later pulses was resolved into a short lived component with a decay half-life of ∼30 ns and a longer lived component with a half-life of ∼400 ns. The latter decay fitted a second order homogeneous rate equation in which the initial concentrations of the two reactants were in the ratio (2.6±0.1):1 and was attributed to the formation of excited OH by electron–ion recombination in the bulk ice. The short lived band II emission was also attributed to excited OH and probably arose from a mixture of a fast intraspur recombination reaction with some other process of different reaction order. Dose accumulation (memory) effects were attributed to the accumulation of OH radicals and lattice vacancies in the irradiated ice. The band III emission had a half-life of 25±5 ns and its decay kinetics were consistent with emission from species such as excited OH− or H3O produced when electrons tunnel from a trapping site to a geminate partner.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.451063
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 19
    Electronic Resource
    Electronic Resource
    Raman study of mesogenic transitions in 4,4'-di-n-pentyloxyazoxybenzene (C5) (1986)
    College Park, Md. : American Institute of Physics (AIP)
    The Journal of Chemical Physics 85 (1986), S. 5273-5278 
    Details
    ISSN: 1089-7690
    Source: AIP Digital Archive
    Topics: Physics , Chemistry and Pharmacology
    Notes: A Raman scattering study of the solid-smectic transition in 4,4'-di-n-pentyloxyazoxybenzene (C5) has been carried out. C5 is known to exhibit a previously unrecognized, highly ordered smectic phase. We have investigated the Raman spectra of C5 in its solid, smectic, nematic, and isotropic phases, with special attention to the external mode region below 100 cm−1. At 300 K the solid phase exhibits several distinct low frequency features. These are progressively attenuated on approaching the solid–smectic transition which occurs at 342 K. The accordion mode of the pentyl chains is observable at 318 cm−1 for the solid phase, but it practically disappears in the smectic phase. This is in accord with the inference of Prasad et al. that the solid–smectic transition is accompanied by a configurational melting of the pentyl end chains. In the smectic phase, an inelastic wing due to a highly damped mode is seen below 60 cm−1; this unique signature of the smectic phase disappears in the nematic and isotropic phases. The plausible origin of this mode and its damping are considered in terms of the molecular correlation within the smectic layers.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.451669
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 20
    Electronic Resource
    Electronic Resource
    Intermolecular interaction in Sn(CH3)4: An inelastic neutron scattering study of matrix isolated molecules (1986)
    College Park, Md. : American Institute of Physics (AIP)
    The Journal of Chemical Physics 85 (1986), S. 5279-5285 
    Details
    ISSN: 1089-7690
    Source: AIP Digital Archive
    Topics: Physics , Chemistry and Pharmacology
    Notes: Rotational tunneling of methyl groups in Sn(CH3)4 molecules isolated in solid argon has been observed by inelastic neutron scattering at (h-dash-bar)ωt =72 μeV. In contrast to the bulk material all CH3 groups are equivalent, and the hindrance potentials is strongly reduced. The tunneling lines show an inhomogeneous broadening which decreases with decreasing concentration of the guest molecules. A discontinuity in the temperature dependence of the tunnel splitting could only be interpreted as due to a spontaneous rearrangement of the guest molecules in the argon lattice. Transitions at 2.1 and 20.7 meV are assigned to a methyl torsion on the basis of the temperature dependence of the tunneling lines and to a scelettal bending mode, respectively. A mode at 11.0 meV (88 cm−1) had not been found by other techniques. It is tentatively assigned to a libration of the Sn(CH3)4 against it cage. An alternative interpretation in a model of coupled methyl groups is also possible. The spectra become similar to the bulk material if the sample is annealed at T∼45 K indicating a clustering of the Sn(CH3)4 molecules to a not completely ordered phase.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.451670
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 21
    Electronic Resource
    Electronic Resource
    Convergence of direct space exchange lattice sums in polymer band structure calculations (1986)
    College Park, Md. : American Institute of Physics (AIP)
    The Journal of Chemical Physics 85 (1986), S. 5286-5298 
    Details
    ISSN: 1089-7690
    Source: AIP Digital Archive
    Topics: Physics , Chemistry and Pharmacology
    Notes: A study of the convergence properties associated with direct lattice summations of the exchange contributions to the quantities needed in a restricted Hartree–Fock calculation for a polymer, leads to a detailed analysis of the analytic and asymptotic properties of the Fock–Dirac density matrix in the LCAO representation. The results, obtained simply by means of Fourier analysis, provide an important characterization of the restricted Hartree–Fock method as applied to chain-like systems. As a by-product we obtain a general proof in direct space that a partially filled band, which influences drastically the analyticity properties of the density matrix in reciprocal space, leads to a logarithmically diverging derivative of the orbital energy at the Fermi level. This in turn gives a vanishing density of states at that level. This result, well known for the electron gas model, is thus an inherent property of the restricted Hartree–Fock approximation.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.451671
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 22
    Electronic Resource
    Electronic Resource
    Generating function methods for macromolecules at surfaces. I. One molecule at a plane surface (1986)
    College Park, Md. : American Institute of Physics (AIP)
    The Journal of Chemical Physics 85 (1986), S. 5299-5305 
    Details
    ISSN: 1089-7690
    Source: AIP Digital Archive
    Topics: Physics , Chemistry and Pharmacology
    Notes: The problem of a macromolecule adsorbed on a single surface is treated by means of a generating function technique. The basic method has the virtues of simplicity and flexibility. The statistical weights that appear in the generating functions for tails, trains, and loops can be calculated with use of a variety of models. The essential physics of the adsorption process, and the occurrence of a critical point, are transparent in this treatment. Illustrative calculations are done for the simplest case, in which tails have unit weight, trains have binding energies proportional to their lengths, and loops are weighted by lattice walk statistics. Methods for treating more realistic models for chains, and for handling their interactions when there is multiple chain adsorption, are discussed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.451672
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 23
    Electronic Resource
    Electronic Resource
    Nonequilibrium structure of the homogeneous phase of block copolymers under steady flow (1986)
    College Park, Md. : American Institute of Physics (AIP)
    The Journal of Chemical Physics 85 (1986), S. 5306-5313 
    Details
    ISSN: 1089-7690
    Source: AIP Digital Archive
    Topics: Physics , Chemistry and Pharmacology
    Notes: A theory is developed to describe the scattering function of a diblock copolymer in the presence of a steady homogeneous flow field. The nonequilibrium steady state under flow conditions is analyzed within a mean field approximation that is expected to accurately describe the disordered phase of block copolymer melts. In the absence of flow the theory reduces to the equilibrium theory of Leibler. Simple shear and extensional flows are seen to render the scattering function highly anisotropic and to attenuate the peak intensity. The instability at the spinodal is predicted to disappear for very strong flows, such as a uniaxial extensional flow. The theory provides an expression for the structure factor that will allow for quantitative interpretation of neutron and x-ray scattering experiments on diblock melts under steady macroscopic flow.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.451673
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 24
    Electronic Resource
    Electronic Resource
    On the nonequilibrium chemical potential of open pores in a membrane (1986)
    College Park, Md. : American Institute of Physics (AIP)
    The Journal of Chemical Physics 85 (1986), S. 5314-5316 
    Details
    ISSN: 1089-7690
    Source: AIP Digital Archive
    Topics: Physics , Chemistry and Pharmacology
    Notes: Starting from the generalized entropy of extended irreversible thermodynamics, we study the influence of the electric current on the probability of finding a system in a state of given energy and electrical conductivity. As an application, we study the probability of open and closed pores in a membrane.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.451674
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 25
    Electronic Resource
    Electronic Resource
    Chemi-ionization reactions of barium with chlorine clusters: Observation of Cl−m and BaCl+m products (m=1–15) (1986)
    College Park, Md. : American Institute of Physics (AIP)
    The Journal of Chemical Physics 85 (1986), S. 2664-2670 
    Details
    ISSN: 1089-7690
    Source: AIP Digital Archive
    Topics: Physics , Chemistry and Pharmacology
    Notes: Chemi-ionization reactions from the collision of Ba with (Cl2) clusters are reported. The scattering yields BaCl+m as well as Cl−m cluster ions. Relative integral cross sections for products with m even or odd depend differently on the collision energy. Over the collision energy range studied of a few eV, channels with odd products predominate, and at higher collision energy constant fractions characterize the observed product pattern. Aspects of the collision mechanism involved are discussed. The analysis suggests these reactions to start within the subsystem Ba+Cl2. The corresponding relative cross section has been determined for Ec.m. ≤2.7 eV.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.451076
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 26
    Electronic Resource
    Electronic Resource
    Molecular beam studies of open-shell systems: The van der Waals interaction between O(3P) and He(1S) (1986)
    College Park, Md. : American Institute of Physics (AIP)
    The Journal of Chemical Physics 85 (1986), S. 5377-5378 
    Details
    ISSN: 1089-7690
    Source: AIP Digital Archive
    Topics: Physics , Chemistry and Pharmacology
    Notes: The absolute integral cross sections for oxygeg atom collisions with helium atoms have been obtained. From these cross sections, the interaction between He and ground state oxygen was calculated.(AIP)
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.451159
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 27
    Electronic Resource
    Electronic Resource
    Comment on "Monte Carlo study of a model of diffusion-controlled reactions'' (1986)
    College Park, Md. : American Institute of Physics (AIP)
    The Journal of Chemical Physics 85 (1986), S. 5382-5383 
    Details
    ISSN: 1089-7690
    Source: AIP Digital Archive
    Topics: Physics , Chemistry and Pharmacology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.451162
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 28
    Electronic Resource
    Electronic Resource
    An analysis of refractory silicate nucleation via the theory of the physical spinodal (1986)
    College Park, Md. : American Institute of Physics (AIP)
    The Journal of Chemical Physics 85 (1986), S. 5380-5381 
    Details
    ISSN: 1089-7690
    Source: AIP Digital Archive
    Topics: Physics , Chemistry and Pharmacology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.451836
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 29
    Electronic Resource
    Electronic Resource
    Radiative lifetimes of the υ'3=0, 1, and 2 levels of CH3S(A˜ 2A1) (1986)
    College Park, Md. : American Institute of Physics (AIP)
    The Journal of Chemical Physics 85 (1986), S. 5379-5380 
    Details
    ISSN: 1089-7690
    Source: AIP Digital Archive
    Topics: Physics , Chemistry and Pharmacology
    Notes: Radiative lifetimes for CH3S(A˜ 2A1) in the υ3 =0, 1, and 2 levels are 760±60, 810±60, and 197±15 ns, respectively. These results are in disagreement with previous work on the υ'3 =0 and 1 levels although in agreement for the υ3 =2 level. Since the previous work was in a beam, it is possible that loss from the viewing region contributed to the shorter lifetimes reported previously for the lower levels. Quenching by (CH3S)2 is fast for all three levels.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.451160
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 30
    Electronic Resource
    Electronic Resource
    Comment on: "On the applicability of Smoluchowski's equation with a constant kernel to coalescence'' (1986)
    College Park, Md. : American Institute of Physics (AIP)
    The Journal of Chemical Physics 85 (1986), S. 5382-5382 
    Details
    ISSN: 1089-7690
    Source: AIP Digital Archive
    Topics: Physics , Chemistry and Pharmacology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.451161
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 31
    Electronic Resource
    Electronic Resource
    Erratum: Towards a full CCSDT model for electron correlation [J. Chem. Phys. 83, 4041 (1985)] (1986)
    College Park, Md. : American Institute of Physics (AIP)
    The Journal of Chemical Physics 85 (1986), S. 5383-5383 
    Details
    ISSN: 1089-7690
    Source: AIP Digital Archive
    Topics: Physics , Chemistry and Pharmacology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.451873
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 32
    Electronic Resource
    Electronic Resource
    Influence of pure reorientational processes on magneto-chiral birefringence and dichroism of diamagnetic molecules in strong optical fields (1986)
    College Park, Md. : American Institute of Physics (AIP)
    The Journal of Chemical Physics 85 (1986), S. 4217-4221 
    Details
    ISSN: 1089-7690
    Source: AIP Digital Archive
    Topics: Physics , Chemistry and Pharmacology
    Notes: The theory of magneto-chiral birefringence and dichroism is extended to systems composed of diamagnetic molecules acted on by an optical field. For molecules with the point group symmetries 3, 4, 6, ∞, 32, 422, and 622 expressions are derived for the magneto-chiral birefringence and dichroism in the presence of weak as well as very strong optical molecular reorientation caused by a linearly polarized, circularly polarized, or unpolarized laser beam. Measurements of magneto-chiral birefringence and dichroism at optical saturation provide direct information on the respective magnetic dipole and electric quadrupole polarizability tensor components.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.451791
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 33
    Electronic Resource
    Electronic Resource
    Measurements of the absolute Raman cross sections of benzene (1986)
    College Park, Md. : American Institute of Physics (AIP)
    The Journal of Chemical Physics 85 (1986), S. 4240-4247 
    Details
    ISSN: 1089-7690
    Source: AIP Digital Archive
    Topics: Physics , Chemistry and Pharmacology
    Notes: The absolute Raman cross sections of the 992 cm−1 (ring breathing) and 3060 cm−1 (C–H stretching) modes of benzene are presented at excitation wavelengths of 514.5, 488.0, 441.6, and 325.0 nm. The technique employs a straightforward determination of the total (unrestricted energy bandwidth) scattering cross section along with a simple relative measurement. The effect of the dispersion of the local field correction (via the frequency dependence of the index of refraction) is found to significantly affect the preresonance benzene cross sections and can distort the normally employed "A-term'' analysis. When the local field effect is incorporated into the data analysis, the results involving neat benzene and previous studies involving 1% benzene in acetonitrile are brought into reasonable agreement. The "n2'' solid angle correction is also verified experimentally using air, water, and benzene as test substances. The preresonance enhancement of the 992 cm−1 mode is found to be consistent with coupling to electronic excitations centered at ∼80 kK which presumably involve the π-electron system. In contrast, the 3060 cm−1 mode is coupled to electronic states centered in the deep ultraviolet, at ∼150 kK, which presumably involve the more energetic σ-electron excitations.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.451795
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 34
    Electronic Resource
    Electronic Resource
    Determination of the structure of HCl BF3 (1986)
    College Park, Md. : American Institute of Physics (AIP)
    The Journal of Chemical Physics 85 (1986), S. 4261-4268 
    Details
    ISSN: 1089-7690
    Source: AIP Digital Archive
    Topics: Physics , Chemistry and Pharmacology
    Notes: The structure of the weakly bound complex HCl BF3 has been determined by molecular beam electric resonance spectroscopy. The molecule is a near prolate symmetric top with the chlorine atom 3.17 A(ring) above the boron atom, on or very near the BF3 threefold axis. The B–Cl–H angle is close to 90°. The spectroscopic constants for the H35Cl11BF3 isotope are (B+C)/2=1774.117(4) MHz, DJ=5.6(5) kHz, eqQa(35Cl)=+25.761(8) MHz, eqQa(11B)=+2.672(25) MHz, and μa=0.484(5)D.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.451798
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 35
    Electronic Resource
    Electronic Resource
    Spectroscopy of N+2 Meinel bands and CO+ comet tail bands (1986)
    College Park, Md. : American Institute of Physics (AIP)
    The Journal of Chemical Physics 85 (1986), S. 4269-4275 
    Details
    ISSN: 1089-7690
    Source: AIP Digital Archive
    Topics: Physics , Chemistry and Pharmacology
    Notes: The N+2[X2 Σ+g(v‘=0)– A 2Πu(v'=5)] Meinel band and the CO+[X 2Σ+(v‘=0)– A 2Π(v'=1,2)] comet tail bands have been measured with Doppler-limited resolution in a selected ion flow tube (SIFT) apparatus using laser induced charge transfer. The charge transfer medium was Ar, which does not react with those ions in their ground levels, but undergoes a strong charge transfer reaction with the excited states under consideration here. The use of a single mode laser and the SIFT technique led to much higher signal-to-noise than obtained in earlier work. These measurements are the first reported with Doppler-limited resolution on any of these bands, and are analyzed to provide substantially improved molecular constants for the excited states involved in the transitions.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.451799
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 36
    Electronic Resource
    Electronic Resource
    Intensity parameters for the Raman trace scattering of ethane (1986)
    College Park, Md. : American Institute of Physics (AIP)
    The Journal of Chemical Physics 85 (1986), S. 4290-4296 
    Details
    ISSN: 1089-7690
    Source: AIP Digital Archive
    Topics: Physics , Chemistry and Pharmacology
    Notes: Absolute Raman trace scattering cross sections have been measured for gaseous ethane-h6 and -d6 and the two rotational conformers of 1,1,2,2-ethane-d4. Sets of ∂α¯/∂Sj intensity parameters were determined for the C2H6/C2D6 pair and for the two CHD2CHD2 isomers; these sets were equal to within the experimental accuracy. The concept of an isotopically independent set of Raman intensity parameters for describing the Raman spectrum of various isotopic species of a molecule is found to be as valid as the concept of an isotopically independent harmonic force field for describing vibrational frequencies.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.451802
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 37
    Electronic Resource
    Electronic Resource
    Broadband near-infrared luminescence of Cr+3 in the elpasolite lattices Cs2NaInCl6, Cs2NaYCl6, and Cs2NaYBr6 (1986)
    College Park, Md. : American Institute of Physics (AIP)
    The Journal of Chemical Physics 85 (1986), S. 4280-4289 
    Details
    ISSN: 1089-7690
    Source: AIP Digital Archive
    Topics: Physics , Chemistry and Pharmacology
    Notes: The broadband luminescence of isolated Cr+3 ions in the title lattices is investigated. The 4T2g lowest excited state is found to undergo Jahn–Teller distortion in the eg coordinate, in addition to expanding along the a1g. Quantitative determination of these displacements is made by analysis of extremely rich fine structure, the Ham quenched spin-orbit splitting of the electronic origins, and the Stokes shifts. The Jahn–Teller effect is found to influence the temperature dependence of lifetimes at less than 50 K. In the yttrium containing hosts, nonradiative deactivation of the 4T2g is observed above 200 K. Analysis of lifetime data with four models for nonradiative decay indicates that the active vibrations are again the a1g and eg. The trends observed among the host materials are rationalized on the basis of the freedom of the 4T2g to relax along the a1g and eg directions.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.451801
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 38
    Electronic Resource
    Electronic Resource
    VUV-optical oscillator strength distributions of C2H6O and C3H8O isomers (1986)
    College Park, Md. : American Institute of Physics (AIP)
    The Journal of Chemical Physics 85 (1986), S. 4276-4279 
    Details
    ISSN: 1089-7690
    Source: AIP Digital Archive
    Topics: Physics , Chemistry and Pharmacology
    Notes: The photoabsorption cross sections of C2H6O isomers (ethyl alcohol and dimethyl ether) and C3H8O isomers (n-propyl alcohol, isopropyl alcohol, and ethyl methyl ether) have been measured in the wavelength region from 30 nm to the ionization potential of each molecule (about 120–130 nm) using an ionization chamber. The obtained photoabsorption cross sections show a maximum value at about 70–80 nm for each molecule. In the wavelength region shorter than about 50 nm, the cross sections are almost the same among isomers and equal to the sum of the cross sections for the constituent atoms. In the longer wavelength region, however, the cross sections show different peaks and shoulders depending on its molecular structure. Especially in the cases of dimethyl ether and ethyl methyl ether vibrational structures of the cross section are observed in the wavelength region from 70 to 100 nm.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.451800
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 39
    Electronic Resource
    Electronic Resource
    The dimethyl ether–sulfur dioxide complex: A photoelectron spectroscopic study (1986)
    College Park, Md. : American Institute of Physics (AIP)
    The Journal of Chemical Physics 85 (1986), S. 4304-4310 
    Details
    ISSN: 1089-7690
    Source: AIP Digital Archive
    Topics: Physics , Chemistry and Pharmacology
    Notes: The He i photoelectron spectrum of the gas-phase complex formed by dimethyl ether and sulfur dioxide has been measured using a pulsed free jet expansion of a mixture of the two gases. A spectrum stripping procedure was used to remove the respective monomer bands from the measured spectrum giving a spectrum assigned to the 1:1 complex (CH3)2O⋅SO2. Interpretation of the spectrum with the aid of ab initio molecular orbital calculations shows that ionization bands associated with (CH3)2O are increased in energy by up to 0.4 eV, whereas those associated with SO2 are decreased in energy by up to 0.9 eV. Ab initio calculations on the dimethyl ether–sulfur dioxide complex, performed at the 3-21G* level, predict an intermolecular O--S separation of 2.355 A(ring) with this direction being displaced 30° from the symmetry axis of the (CH3)2O but approximately perpendicular to the SO2 molecular plane. The monomer dipoles are oriented approximately antiparallel in the complex.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.451803
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 40
    Electronic Resource
    Electronic Resource
    Fluorescence polarization theory for asymmetric rotors: Rotational dynamics in the regular and statistical limits (1986)
    College Park, Md. : American Institute of Physics (AIP)
    The Journal of Chemical Physics 85 (1986), S. 4311-4321 
    Details
    ISSN: 1089-7690
    Source: AIP Digital Archive
    Topics: Physics , Chemistry and Pharmacology
    Notes: Classical and quantum theories of ensemble averaged fluorescence polarization are presented for the asymmetric rotor in the regular, rigid rotor limit and in the limit of statistical vibration–rotation energy transfer in the isolated molecule. Planar asymmetric rotors are explored in detail, with special emphasis on p-difluorobenzene and pyrimidine. The classical polarizations are nearly identical to the quantum results, but are 1000 times faster to calculate. For nearly all molecular geometries, our results predict the transition from regular to statistical rotational motion will sharply reduce the fluorescence polarization, signaling the onset of intramolecular vibration–rotation energy transfer.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.451804
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 41
    Electronic Resource
    Electronic Resource
    Millimeter-wave optical double resonance spectra of NO2: How good a quantum number is N? (1986)
    College Park, Md. : American Institute of Physics (AIP)
    The Journal of Chemical Physics 85 (1986), S. 4297-4303 
    Details
    ISSN: 1089-7690
    Source: AIP Digital Archive
    Topics: Physics , Chemistry and Pharmacology
    Notes: Optical transitions to the 2B2 electronic state region of NO2 have been observed in double resonance with three millimeter-wave ground state rotational transitions. The probed ground state transitions were the N=2 (F1), N=4 (F1), and N=10 (F2), K=0→1 Q branch transitions near 250 GHz. The optical range scanned was 16 800 to 16 950 cm−1. The 100,10–101,9 F2 spectrum was combined with previous double resonance results with the ground state 91,9–100,10 F1 transition. This comparison shows 70 out of 160 upper states with J=19/2 to have indefinite or mixed N values. It establishes violations of the ΔN=ΔJ selection rule in this spectral region which contains bands with a wide range of spin-rotation constants. Lack of intensity correlation between the two spectra suggests two classes of upper states are present: a group of strongly N-mixed upper states, and a group essentially unmixed in N. Heller's F parameter, which measures the fraction of all possible symmetry-restricted basis states contributing to a typical eigenstate, is similar for the double-resonance spectra of the three N values, but is greater for K=1 than for K=0. By finding upper states in common, R lines from N=2 and P lines from N=4 have been identified.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.451825
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 42
    Electronic Resource
    Electronic Resource
    Time domain formulation of optical spectroscopy involving three potential energy surfaces (1986)
    College Park, Md. : American Institute of Physics (AIP)
    The Journal of Chemical Physics 85 (1986), S. 4322-4340 
    Details
    ISSN: 1089-7690
    Source: AIP Digital Archive
    Topics: Physics , Chemistry and Pharmacology
    Notes: We consider the computation of electronic absorption and Raman scattering spectra when three potential energy surfaces are involved; namely, a ground state surface coupled radiatively to one excited state which is in turn coupled nonadiabatically to a second excited surface. Frequency domain formulas are given for both kinds of spectra under the (standard) assumption of weak radiative coupling, but with no restriction on the nonadiabatic coupling strength. These formulas are transcribed into the time domain so that the computational burden is shifted to determination of the temporal evolution of wave packets simultaneously on both excited surfaces. We show how to implement the appropriate dynamics utilizing a perturbation expansion in the nonadiabatic coupling strength. Finally, extensive numerical results are presented for a one dimensional test system. Lowest order nonvanishing perturbation theory corrections are found to account accurately for nonadiabatic effects of ∼15%. Concentrating mainly on low resolution spectra such as arise in the case of direct photodissociation, the general effect of nonadiabatic coupling is observed to be broadening of absorption spectra and suppression of Raman scattering intensities.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.451805
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 43
    Electronic Resource
    Electronic Resource
    Intra- and intermolecular energy transfer in H2+OH collisions (1986)
    College Park, Md. : American Institute of Physics (AIP)
    The Journal of Chemical Physics 85 (1986), S. 4348-4361 
    Details
    ISSN: 1089-7690
    Source: AIP Digital Archive
    Topics: Physics , Chemistry and Pharmacology
    Notes: We have used the method of quasiclassical dynamics to investigate intra- and intermolecular energy transfer in H2+OH collisions. Energy transfer has been investigated as function of translational temperature, rotational energy, and vibrational energy. The energy transfer mechanism is complex with ten types of energy transfer possible, and evidence was found for all types. There is much more exchange between the translational degree of freedom and the H2 vibrational degree of freedom than there is between translation and OH vibration. Translational energy is transferred to the rotational degrees of freedom of each molecule, and this occurs more readily for OH than H2. Both molecules exhibited intramolecular energy transfer from vibration to rotation, and this was a major pathway for vibrational deactivation. Evidence was also found for the intermolecular transfer of energy from vibration to the rotational and vibrational degrees of freedom of the other molecule.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.451860
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 44
    Electronic Resource
    Electronic Resource
    Picosecond photoisomerization and rotational reorientation dynamics in solution (1986)
    College Park, Md. : American Institute of Physics (AIP)
    The Journal of Chemical Physics 85 (1986), S. 4341-4347 
    Details
    ISSN: 1089-7690
    Source: AIP Digital Archive
    Topics: Physics , Chemistry and Pharmacology
    Notes: The trans–cis isomerization rates for stiff-diphenylbutadiene (S-DPB) in n-alkane solvents were measured using single photon counting methods and the rotational reorientation times τR for S-DPB and trans stilbene were obtained by picosecond polarization spectroscopy. In neither case did τR vs viscosity show Stokes–Einstein–Debye (SED) behavior. The values of τR were used to calculate the angular velocity correlation frequencies β using the Hubbard relation. The variation of isomerization rate with β was found to be predicted well by the Kramers equation when barrier frequencies of 154 cm−1 for stilbene and 16 cm−1 for S-DPB were used. This Kramers-Hubbard fit finesses questions regarding the validity of the one dimensional Kramers model and focuses attention on the SED equation. The dynamical relationship between the torsional friction, important in isomerization, and rotational friction, which determines the overall angular motion of the molecules, is discussed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.451806
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 45
    Electronic Resource
    Electronic Resource
    Photodissociation of vibrationally excited OCS (1986)
    College Park, Md. : American Institute of Physics (AIP)
    The Journal of Chemical Physics 85 (1986), S. 4362-4372 
    Details
    ISSN: 1089-7690
    Source: AIP Digital Archive
    Topics: Physics , Chemistry and Pharmacology
    Notes: A two-step photodissociation method has been used to measure the photodissociation cross section of vibrationally excited OCS(ν1) at λ=249 nm. The method employs an NH3 laser to pump OCS molecules to the ν1=1 vibrational state, followed by photodissociation by a KrF excimer laser and mass spectrometric analysis of the chemically scavenged photodissociation products. The experiments determine the photodissociation cross section ratio σ d(ν1)/σ d295 K =4.5±0.9, where σ d295 K is the 249 nm photodissociation cross section of thermal (295 K) OCS. An analysis of our previously reported data for the ν2=2 vibrational state of OCS gives the photodissociation cross section ratio σ d(2ν2)/σ d295 K =8.4±1.1. The measured cross section ratios are used in an analysis of temperature dependent photoabsorption spectra to obtain the photoabsorption cross section ratios σ a(0)/σ a295 K =0.41±0.04 and σ a(ν2)/σ a295 K =2.5±0.6 for the vibrationless and ν2=1 states of OCS, respectively. Isotopically selective, two-step photodissociation through the OCS(ν1) vibrational state was used to separate 33S or 34S isotopes with enrichment factors of β=2.2.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.451807
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 46
    Electronic Resource
    Electronic Resource
    Superconducting and other phases in organic high polymers of polyacenic carbon skeletons. I. The method of sum of divergent perturbation series (1986)
    College Park, Md. : American Institute of Physics (AIP)
    The Journal of Chemical Physics 85 (1986), S. 3090-3096 
    Details
    ISSN: 1089-7690
    Source: AIP Digital Archive
    Topics: Physics , Chemistry and Pharmacology
    Notes: The instabilities of a normal molecular orbital state of polyacenic materials are studied within RPA with a g model for an electronic interaction. The condensed states predicted are singlet superconducting (SSC), charge density wave (CDW), and spin density wave (SDW) ones, and their phase diagram is shown. In contrast to usual one-dimensional (1D) conductors, there reveals a wide range of superconducting state, which is not overcome by CDW transition. Weakness of Peierls distortion of the present model is also contrasted with the case of polyacetylene.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.451017
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 47
    Electronic Resource
    Electronic Resource
    Gas-phase hydrolysis of SOF2 and SOF4 (1986)
    College Park, Md. : American Institute of Physics (AIP)
    The Journal of Chemical Physics 85 (1986), S. 4377-4380 
    Details
    ISSN: 1089-7690
    Source: AIP Digital Archive
    Topics: Physics , Chemistry and Pharmacology
    Notes: The rates for gas-phase hydrolysis of SOF2 (thionylfluoride) and SOF4 (thionyl tetrafluoride) have been measured at a temperature of 298 K. The second order rate constant for SOF2 hydrolysis in SF6 buffer gas was found to have the value (1.2±0.3)×10−23 cm3/s which agrees with previous estimates of Sauers et al., but is three orders of magnitude lower than the value obtained by Rüegsegger et al. at 340 K. The rate constant for SOF4 hydrolysis has not previously been measured and its value in both SF6 and N2 buffer gases was found here to be (1.0±0.3)×10−21 cm3/s.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.451809
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 48
    Electronic Resource
    Electronic Resource
    Preselecting paths for multiphoton dynamics using artificial intelligence (1986)
    College Park, Md. : American Institute of Physics (AIP)
    The Journal of Chemical Physics 85 (1986), S. 1826-1839 
    Details
    ISSN: 1089-7690
    Source: AIP Digital Archive
    Topics: Physics , Chemistry and Pharmacology
    Notes: A new, systematic method for selecting the most important basis functions by using an artificial intelligence tree pruning algorithm is introduced. The technique can be applied to any physical problem which gives rise to coupled equations but is applicable in general to any problem which could benefit from an orderly exploration of linked alternatives in a decision tree. The method is applied here to select the most important states for modeling the multiphoton dynamics of a general vibrating–rotating spherical top molecule. The optimal paths selected by the branch-and-bound search algorithm augmented with dynamic programming are investigated in detail with respect to what information about the dynamics they may contain.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.451184
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 49
    Electronic Resource
    Electronic Resource
    Classical dynamics study of intramolecular energy flow in benzene (1986)
    College Park, Md. : American Institute of Physics (AIP)
    The Journal of Chemical Physics 85 (1986), S. 1848-1853 
    Details
    ISSN: 1089-7690
    Source: AIP Digital Archive
    Topics: Physics , Chemistry and Pharmacology
    Notes: The flow of energy from highly excited CH overtones in benzene is investigated by quasiclassical trajectory methods for atomic motions restricted to the molecular plane. Various initial conditions and potential-energy surfaces (harmonic and anharmonic) are examined. The results are in accord with the rapid energy transfer rates observed in experiments. Comparisons are made with other theoretical studies.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.451186
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 50
    Electronic Resource
    Electronic Resource
    The determination of the vector correlation between photofragment rotational and translational motions from the analysis of Doppler-broadened spectral line profiles (1986)
    College Park, Md. : American Institute of Physics (AIP)
    The Journal of Chemical Physics 85 (1986), S. 1866-1879 
    Details
    ISSN: 1089-7690
    Source: AIP Digital Archive
    Topics: Physics , Chemistry and Pharmacology
    Notes: A theoretical framework is presented to describe the possible correlation between the translational and rotational motion of a molecular photofragment, and to relate this to experimental observables. The correlation is defined by the values of a number of bipolar moments of the translational and rotational angular distributions which reflect the dynamics of the dissociation process. Detailed equations are presented for the polarization dependence of the profiles of recoil Doppler–broadened spectral lines of the photoproduct for two distinct classes of system: (i) molecular photodissociation, followed by spontaneous fluorescence by a molecular product with dispersion of its emission spectrum, and (ii) LIF excitation of a photoproduct, with or without dispersion of the resulting emission. The application of the theory is illustrated by calculating the line profiles for two model systems, each with several excitation–detection geometries. It is pointed out that there may still be detectable correlation between the product motions even for weakly predissociated parent molecule transitions in which the memory of the initial excitation is lost through extensive rotation before dissociation.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.451131
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 51
    Electronic Resource
    Electronic Resource
    Quenching of OH(A 2Σ+, v'=0) by NH3 from 250 to 1400 K (1986)
    College Park, Md. : American Institute of Physics (AIP)
    The Journal of Chemical Physics 85 (1986), S. 1898-1903 
    Details
    ISSN: 1089-7690
    Source: AIP Digital Archive
    Topics: Physics , Chemistry and Pharmacology
    Notes: The rate constant for collisional removal of the v′=0 level of the A 2Σ+ excited state of the OH radical by NH3 is measured over the temperature range 250–1400 K. The thermally averaged cross section σQ near room temperature is roughly twice its value at 900 K of ∼40 A(ring)2. Between 850 and 1400 K, no variation of σQ with temperature is observed. This temperature dependence is consistent with a quenching mechanism dominated by long range attractive forces.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.451133
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 52
    Electronic Resource
    Electronic Resource
    A test of two approximate two-state treatments for the dynamics of H-atom transfers between two heavy particles (1986)
    College Park, Md. : American Institute of Physics (AIP)
    The Journal of Chemical Physics 85 (1986), S. 1924-1930 
    Details
    ISSN: 1089-7690
    Source: AIP Digital Archive
    Topics: Physics , Chemistry and Pharmacology
    Notes: Reactive transition probabilities and Boltzmann-averaged reactive transition probabilities for a slightly off-resonant model H-atom transfer system with an appreciable energy barrier are calculated using the approximate methods of Babamov et al. and of Crothers–Stückelberg. Both are compared with the corresponding quantities obtained from a numerical two-state treatment of the same model system. The method of Babamov et al. is seen to give more accurate results for the transition probabilities at energies below and around the reaction threshold, and much more accurate results for the Boltzmann-averaged probabilities in a wide range of temperatures than the second method. The relative merits of the two formulas are discussed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.451835
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 53
    Electronic Resource
    Electronic Resource
    Effective dephasing theory of the optical Anderson transition as probed by four-wave-mixing spectroscopy (1986)
    College Park, Md. : American Institute of Physics (AIP)
    The Journal of Chemical Physics 85 (1986), S. 1950-1965 
    Details
    ISSN: 1089-7690
    Source: AIP Digital Archive
    Topics: Physics , Chemistry and Pharmacology
    Notes: A novel theory of quantum mechanical transport in disordered systems is developed. The theory is based on the effective dephasing approximation (EDA), in which the ensemble averaged Liouville space propagator is mapped into the propagator of an ordered lattice with an effective frequency-dependent dephasing rate. This generalized dephasing rate is determined self-consistently. This approach is applicable to strongly disordered systems and yields results that interpolate between the limits of coherent and incoherent excitation transport and that predict the optical analog of a metal–insulator phase transition (Anderson localization). Our results agree with the predictions of the scaling theory of the Anderson transition. We apply the EDA to the calculation of the transient grating signal from a crystal with an inhomogeneously broadened absorption spectrum (static, site energy disorder). The transient grating experiment is shown to be a sensitive probe of the optical Anderson transition.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.451138
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 54
    Electronic Resource
    Electronic Resource
    Autoionization and isotope effect in the threshold photoelectron spectrum of 12CO2 and 13CO2 (1986)
    College Park, Md. : American Institute of Physics (AIP)
    The Journal of Chemical Physics 85 (1986), S. 4765-4778 
    Details
    ISSN: 1089-7690
    Source: AIP Digital Archive
    Topics: Physics , Chemistry and Pharmacology
    Notes: Threshold photoelectron spectra of 12CO2 and 13CO2 have been obtained from the onset at 900 A(ring) (13.75 eV) to 620 A(ring) (20 eV) at a 9 meV resolution using dispersed synchrotron radiation with a 0.3 A(ring) bandpass. A number of forbidden and/or previously unobserved transitions have been assigned for the X˜, A˜, B˜, and C˜ states of CO+2. Photoelectron spectra by electron time of flight at selected excitation wavelengths in the Franck–Condon gap region below the A˜ state, reveal the autoionization of neutral valence states as well as Rydberg series converging to the A˜ 2Πu and B˜ 2Σ+u states. The photoelectron energy distribution obtained upon excitation of the Rydberg states is consistent with that given by the Bardsley–Smith model for autoionization, while the superexcited valence states decay via a resonance autoionization process proposed previously by Guyon, Baer, and Nenner. These valence states are also responsible for the strong enhancement of vibrationally forbidden transitions, such as (000)→(010). Finally, several threshold electron peaks in the region between the A˜ and C˜ states, whose origin can be attributed to autoionization, are shown to be highly sensitive to isotopic substitution.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.451736
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 55
    Electronic Resource
    Electronic Resource
    The Raman-active O–H and O–D stretching vibrations and Raman spectra of gaseous formic acid-d1 and -OD (1986)
    College Park, Md. : American Institute of Physics (AIP)
    The Journal of Chemical Physics 85 (1986), S. 4779-4789 
    Details
    ISSN: 1089-7690
    Source: AIP Digital Archive
    Topics: Physics , Chemistry and Pharmacology
    Notes: In keeping with current theoretical activity concerning the OH and OD stretching bands of the carboxylic acids, we report the Raman spectra of gaseous formic acid-OD and formic acid-d1 for the first time. We emphasize the OH and OD stretching bands, which can be studied cleanly in these isotopomers but not in normal or perdeuterated formic acid. The spectra of the dimers and monomers below 2000 cm−1 are assigned, and current knowledge of the vibrations of the molecules is summarized. The Raman spectra allow the estimation of the energies of the Bu combination levels that may be in Fermi resonance with the infrared active Bu, OH or OD stretching fundamental, as well as those of the Ag overtone and combination levels that may interact with the Raman-active stretching fundamental. We conclude that the sharp features on the Raman OH and OD stretching bands are due to overtone and combination transitions, that the stretching modes cause the underlying broad scattering, namely three broad bands, centered at 2430, 2270, and 2080 cm−1 for (HCOOD)2 and at 3240, 3074, and 2880 cm−1 for (DCOOH)2. We further conclude that the higher and lower frequency broad bands are due to sum and difference transitions with the hydrogen bond modes, which lie between 60 and 240 cm−1. The infrared OD and OH stretching bands of (HCOOD)2 and (DCOOH)2 are consistent with this interpretation. The Raman OD stretching band of HCOOD ⋅ HCOOH coincides with that of (HCOOD)2 apart from the overtone and combination transitions. The centers of Raman intensity, corrected for instrument, wave number, and temperature dependencies, of the OD stretching bands of (HCOOD)2 and HCOOH ⋅ HCOOD are 2300 ±5 and 2305 ±10 cm−1, respectively, and that of the OH stretching band of (DCOOH)2 is 3035±10 cm−1. This data and the near coincidence of the infrared and Raman bands of (HCOOD)2 show that the vibrational coupling of the two OD bonds in the dimer is not unusually large. Comparison of the infrared and Raman OH stretching bands indicates a larger coupling between OH oscillators. These results agree with earlier result for acetic acid.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.451737
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 56
    Electronic Resource
    Electronic Resource
    A photoionization study of SeH and H2Se (1986)
    College Park, Md. : American Institute of Physics (AIP)
    The Journal of Chemical Physics 85 (1986), S. 4815-4824 
    Details
    ISSN: 1089-7690
    Source: AIP Digital Archive
    Topics: Physics , Chemistry and Pharmacology
    Notes: The photoion yield curve of SeH, prepared by the reaction H+H2Se is presented. The adiabatic I.P. is 9.845±0.003 eV, and autoionization structure is observed, from which higher I.P.'s are inferred. The photoion yield curves of H2Se+, SeH+, and Se+ from H2Se are also measured. The fragmentation thresholds, together with I.P. (SeH), enable one to infer the bond energies D0(HSe−H)=78.99±0.18 kcal/mol and D0(SeH)=74.27±0.23 kcal/mol. The adiabatic I.P. for H2Se (X˜ 2B) is 9.886±0.003 eV.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.451715
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 57
    Electronic Resource
    Electronic Resource
    Rate constant for the reaction of O(3P) with diacetylene from 210 to 423 K (1986)
    College Park, Md. : American Institute of Physics (AIP)
    The Journal of Chemical Physics 85 (1986), S. 3300-3304 
    Details
    ISSN: 1089-7690
    Source: AIP Digital Archive
    Topics: Physics , Chemistry and Pharmacology
    Notes: The absolute rate constant for the reaction of O(3P) with diacetylene (C4H2) has been measured as a function of pressure and temperature by the flash photolysis-resonance fluoresence method. At 298 K and below, no pressure dependence of the rate constant was observed but at 423 K a moderate (factor of 2) increase was detected in the range 3 to 75 Torr Ar. Results at or near the high pressure limit are well represented by the Arrhenius expression k1=(1.31±0.12)×10−11 exp[−(678±23)/T] cm3 s−1 over the temperature range 210 to 423 K. The results are compared with previous determinations, all of which employed the discharge flow-mass spectrometry technique. The mechanism of the reaction is considered including both primary and secondary processes. The heats of formation of the reactants, adducts, and products for the O(3P)+C4H2 reaction are discussed and contrasted with those for O(3P)+C2H2.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.450950
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 58
    Electronic Resource
    Electronic Resource
    Semiclassical calculation of eigenvalues for higher order resonances in nonseparable oscillator systems (1986)
    College Park, Md. : American Institute of Physics (AIP)
    The Journal of Chemical Physics 85 (1986), S. 3305-3312 
    Details
    ISSN: 1089-7690
    Source: AIP Digital Archive
    Topics: Physics , Chemistry and Pharmacology
    Notes: It is shown how the "trajectory-close method'' introduced in earlier papers of this series can be used to treat other resonant systems semiclassically. The method, which does not involve the use of any curvilinear coordinate system, is illustrated for two coupled oscillators which have 3:1, 4:1, 5:1, 3:2, and 5:2 internal resonances. It is readily executed and it is shown how it can be extended to the three-oscillator case. This work supplements our earlier studies of 1:1, 2:1, and 3:1 resonant systems using this technique. Shapes of eigentrajectories and of corresponding quantum mechanical wave functions are compared for each of these systems. The paper also contains a survey of and comparison with other semiclassical methods which have been applied to systems with internal resonances.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.450951
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 59
    Electronic Resource
    Electronic Resource
    Vibrational state resolved measurements of differential cross sections for H++O2 charge transfer collisions (1986)
    College Park, Md. : American Institute of Physics (AIP)
    The Journal of Chemical Physics 85 (1986), S. 3313-3325 
    Details
    ISSN: 1089-7690
    Source: AIP Digital Archive
    Topics: Physics , Chemistry and Pharmacology
    Notes: Vibrational state-to-state charge transfer cross sections have been obtained for H++O2 collisions at Ecm =23.0 eV in a differential scattering experiment by measuring the product H atom energy distribution in the range 0°≤θ≤11°. The results show a strong dependence of the distribution of vibrational transition probabilities P(O2, v=0→O+2, v″) on the scattering angle. At very low angles (θ(approximately-less-than)2°) we find a strongly enhanced contribution of the more resonant states v″=3–6 compared to a Franck–Condon distribution, which is peaked at v″=1 and, on the other hand, at moderate angles of about θ=4° comes very close to the measured spectra. At even larger angles increasing deviations from the Franck–Condon distribution towards larger excitation of higher vibrational states are observed. An explanation of these and the related results for the nonexchange collisions leading to neutral O2 vibrational excitation is given in terms of the underlying potential energy surfaces.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.450952
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 60
    Electronic Resource
    Electronic Resource
    The vibrational predissociation lifetime of the HF dimer upon exciting the "free-H'' stretching vibration (1986)
    College Park, Md. : American Institute of Physics (AIP)
    The Journal of Chemical Physics 85 (1986), S. 3338-3341 
    Details
    ISSN: 1089-7690
    Source: AIP Digital Archive
    Topics: Physics , Chemistry and Pharmacology
    Notes: A computer controlled F-center laser has been used, in conjunction with a molecular beam apparatus employing optothermal detection, to obtain an accurate measurement of the vibrational predissociation lifetime of the HF dimer following ν1 vibrational excitation. The lifetime obtained in this study is 24±2 ns. This is to be compared with a lifetime for ν2 excitation of 1.0±0.1 ns.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.450955
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 61
    Electronic Resource
    Electronic Resource
    State-to-state excitation of NO(A 2Σ+, v′=0,1,2) by N2(A 3Σ+u, v′=0,1,2) (1986)
    College Park, Md. : American Institute of Physics (AIP)
    The Journal of Chemical Physics 85 (1986), S. 3369-3378 
    Details
    ISSN: 1089-7690
    Source: AIP Digital Archive
    Topics: Physics , Chemistry and Pharmacology
    Notes: We have determined that the rate coefficient for quenching N2(A 3Σ+u, v′=0) by NO is (6.6±1.0)×10−11 cm3 molecule−1 s−1. Higher levels of N2(A) appear to be quenched with a similar rate coefficient. Separate studies show that the rate coefficient for the excitation of NO(A 2Σ+, v′=0−2) by N2(A 3Σ+u, v′=0) is (10±3)×10−11 cm3 molecule−1 s−1. The apparent discrepancy between the quenching and excitation rate coefficient measurements most likely results from an error in the accepted value of the lifetime N2(A). Our studies indicate that this lifetime is probably about 30% longer than currently believed. We also report rate coefficients for excitation of each of the vibrational levels 0–2 of NO(A) by each of the vibrational levels 0–2 of N2(A) relative to the rate coefficient for excitation of NO(A, v′=0) by N2(A, v′=0).
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.450958
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 62
    Electronic Resource
    Electronic Resource
    Studies of reactions of importance in the stratosphere. VI. Temperature dependence of the reactions O+NO2→NO+O2 and O+ClO→Cl+O2 (1986)
    College Park, Md. : American Institute of Physics (AIP)
    The Journal of Chemical Physics 85 (1986), S. 3359-3368 
    Details
    ISSN: 1089-7690
    Source: AIP Digital Archive
    Topics: Physics , Chemistry and Pharmacology
    Notes: The reactions of two free radicals, nitrogen dioxide and chlorine monoxide, with oxygen atoms, O+NO2→NO+O2 and O+ClO→Cl+O2, have been investigated in a fast flow system over the temperature range 220–387 K, at a total pressure of 2.3 Torr. Reaction rates were measured under psuedo-first-order conditions with either ClO or NO2 in large excess and the decay of oxygen atoms monitored by adding nitric oxide at the end of the flow tube and detecting the O+NO+M chemiluminescence. The reactions are of interest, because they are thought to be the rate determining steps in two catalytic chains which destroy odd oxygen (O and O3) in the stratosphere. Measurements of the rate constants over the stated temperature interval yielded the Arrhenius expressions kO+NO2=(6.58±0.52)×10−12 exp[(142±23)/T] and kO+ClO=(2.61±0.60)×10−11 exp[(97±64)/T]. Thus, both reactions display small negative activation energies. In addition, experiments showed no pressure effect on the reaction rate in the range 2.3–5.3 Torr and at a temperature of 230 K. Addition of a partial pressure of 1 Torr of oxygen also had no effect on the rate constant at 230 K, suggesting that ClO ⋅ O2 formation is of little or no significance under stratospheric conditions.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.450957
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 63
    Electronic Resource
    Electronic Resource
    Energy dissipation mechanism of the optically excited molecules in solvents: A trajectory study for a photoisomerization process of the π-conjugated molecule in Ar and water (1986)
    College Park, Md. : American Institute of Physics (AIP)
    The Journal of Chemical Physics 85 (1986), S. 3342-3358 
    Details
    ISSN: 1089-7690
    Source: AIP Digital Archive
    Topics: Physics , Chemistry and Pharmacology
    Notes: The energy dissipation mechanism of an optically excited molecule in solution is studied by using a classical molecular dynamics (MD) calculation. We chose ethylene in Ar or water as a model system and perform the MD calculation to analyze the solvent response to the optically excited ethylene motions that are large in magnitude and high in frequency. It is found that the energy dissipation is very fast; it is in the order of a picosecond in water and of a few to a few tens of picoseconds in Ar. The energy decay rate strongly depends on each ethylene mode and on the nature of solvent–solvent interaction. Due to the characteristic form of water–water interaction, that is strong and sensitive to the mutual geometrical changes, a large water kinetic fluctuation occurs. The ethylene motions couple to this water fluctuation efficiently transferring the ethylene energy to the water libration energy, that is immediately distributed into the various inter- and intrawater modes. A multistep collision process leading the energy flow from the ethylene internal vibration→the ethylene rotation→the solvent molecule motion, not accounted for in the gas-like models such as isolated binary collision model, is a pathway for the fast energy dissipation in Ar and water. We also employ a simple model of an oscillator in Ar to make a detail analysis of the energy decay mechanism, especially of its dependence on the oscillator amplitude, the solvent–solvent interaction, and the solvent density.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.450956
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 64
    Electronic Resource
    Electronic Resource
    Production of OH from the collision-free photodissociation of nitromethane at 266 nm (1986)
    College Park, Md. : American Institute of Physics (AIP)
    The Journal of Chemical Physics 85 (1986), S. 3395-3400 
    Details
    ISSN: 1089-7690
    Source: AIP Digital Archive
    Topics: Physics , Chemistry and Pharmacology
    Notes: Photodissociation of nitromethane, CH3NO2, at 266 nm under collision-free conditions results in the single photon production of electronic ground state OH(X 2Πi). A rotational "temperature'' of 1750±50 K describes the rotational distribution of the nascent OH radical. A quantum yield of 0.004±0.001 is determined for the photolytic pathway producing the OH radical. Within experimental uncertainty, no Λ-doublet population preference was observed for OH production from H2O2, HNO3, or CH3NO2 photolysis. If a saturation correction is not utilized apparent Λ-doublet population differences are found. This incorrect saturation compensation may account for previous literature Λ-doublet population ratios, fi/ f′i, that are greater than one.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.450961
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 65
    Electronic Resource
    Electronic Resource
    van der Waals rovibrational states of atom–molecule complexes: Ar–benzene and Ar–tetrazine (1986)
    College Park, Md. : American Institute of Physics (AIP)
    The Journal of Chemical Physics 85 (1986), S. 3411-3424 
    Details
    ISSN: 1089-7690
    Source: AIP Digital Archive
    Topics: Physics , Chemistry and Pharmacology
    Notes: Using an empirical intermolecular potential, we have calculated the van der Waals modes of the atom–molecule complexes Ar–benzene and Ar–tetrazine. In the lower states the atom appears as being localized on one side of the molecular plane. This spectrum can be interpreted qualitatively in terms of one- or two-dimensional oscillators. However, these a very anharmonic and especially the motions along the molecular plane have large amplitudes. At higher energies the increased density of states will lead to an increased coupling between the modes. Furthermore, we have calculated the rotational constants of the complex, which are found to be a good measure for the quality of the ground state potential.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.450963
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 66
    Electronic Resource
    Electronic Resource
    An ab initio study of the molecular electric polarizabilities of N2, HCN, acetylene, and diacetylene (1986)
    College Park, Md. : American Institute of Physics (AIP)
    The Journal of Chemical Physics 85 (1986), S. 3432-3436 
    Details
    ISSN: 1089-7690
    Source: AIP Digital Archive
    Topics: Physics , Chemistry and Pharmacology
    Notes: The independent components of the α, β, γ, A, and B tensors were computed for the ground states of N2, HCN, acetylene, and diacetylene molecules from electric moments induced in a perturbing static electric field. The results are used to comment on trends in nonlinear susceptibilities of polyacetylenes and polydiacetylenes.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.450965
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 67
    Electronic Resource
    Electronic Resource
    The classical and nonclassical forms of protonated acetylene, C2H+3. Structures, vibrational frequencies, and infrared intensities from explicitly correlated wave functions (1986)
    College Park, Md. : American Institute of Physics (AIP)
    The Journal of Chemical Physics 85 (1986), S. 3437-3443 
    Details
    ISSN: 1089-7690
    Source: AIP Digital Archive
    Topics: Physics , Chemistry and Pharmacology
    Notes: The vibrational frequencies and IR intensities of C2H+3 and C2D+3 have been predicted using the methods of ab initio molecular quantum mechanics. Specifically, configuration interaction (CI) wave functions have been constructed from double zeta plus polarization (DZ+P) basis sets. In addition, a much larger basis set, triple zeta plus diffuse plus double polarization, has been used at the self-consistent-field (SCF) level of theory. The results are qualitatively similar to those (at much lower levels of theory) reported earlier by Raine and Schaefer. At the highest level of theory, CI including all single, double, and triple excitations (213 780 configurations for the classical structure), the nonclassical structure is the lower by only 0.7 kcal/mol.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.451828
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 68
    Electronic Resource
    Electronic Resource
    The polarization-function counterpoise method. An application of the diagrammatic perturbation theory to the He–H2 molecule in the region of the van der Waals minimum (1986)
    College Park, Md. : American Institute of Physics (AIP)
    The Journal of Chemical Physics 85 (1986), S. 3448-3457 
    Details
    ISSN: 1089-7690
    Source: AIP Digital Archive
    Topics: Physics , Chemistry and Pharmacology
    Notes: The results of the calculation on the C∞v He–H2 van der Waals molecule by employing the diagrammatic many-body theory to treat the electron correlation effects are reported in this paper. The use of the partial counterpoise method to compute the self-consistent field (SCF) and correlation energies, when a moderate basis set is employed, may lead to a reliable description of the potential curve for the van der Waals (VDW) system.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.450967
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 69
    Electronic Resource
    Electronic Resource
    A model potential for Rydberg states of alkali atoms in rare gas matrices (1986)
    College Park, Md. : American Institute of Physics (AIP)
    The Journal of Chemical Physics 85 (1986), S. 3458-3462 
    Details
    ISSN: 1089-7690
    Source: AIP Digital Archive
    Topics: Physics , Chemistry and Pharmacology
    Notes: The term values of the ground and excited Rydberg states of alkali metal atoms trapped in rare gas matrices are derived from an empirical model potential. The analytical potential smoothly connects the Coulomb potential near the core with the shielded Coulomb potential beyond the first shells of surrounding matrix atoms. The potential does not depend on the specific dopant and is determined for each rare gas matrix in a unique way from the polarization energy of the crystal by the ionic core P+ and from the electron affinity V0. The predicted transition energies agree with the experimental data within 0.1 to 0.2 eV.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.450968
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 70
    Electronic Resource
    Electronic Resource
    Laboratory studies of gas phase sodium diffusion (1986)
    College Park, Md. : American Institute of Physics (AIP)
    The Journal of Chemical Physics 85 (1986), S. 3469-3475 
    Details
    ISSN: 1089-7690
    Source: AIP Digital Archive
    Topics: Physics , Chemistry and Pharmacology
    Notes: The gas phase diffusion coefficients of Na in Ne, N2, and CO2 were measured in a flow tube with an oven source and resonant fluoresence detection of Na. DNa,Ne=209±21 cm2 Torr s−1 at 281 K, DNa,N2=129±13 cm2 Torr s−1 at 281 K, and DNa,CO2=134±13 cm2 Torr s−1 at 281 K. DNa,He was measured over the temperature range 211– 424 K. DNa,He(T)=(385±40) (T/300)(1.72±0.18) cm2 Torr s−1. The experimental results are compared with previous studies. The sticking coefficient for Na on the walls of the flow tube was determined to be approximately equal to 1 by an analysis of the diffusion coefficient data. The results for DNa,He, DNa,Ne, and DNa,Ar are compared with the predictions of Chapman–Enskog calculations using Na–noble gas potentials from recent spectroscopic measurements.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.450970
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 71
    Electronic Resource
    Electronic Resource
    Statistical moments for random two-phase suspensions: A computational framework (1986)
    College Park, Md. : American Institute of Physics (AIP)
    The Journal of Chemical Physics 85 (1986), S. 3505-3514 
    Details
    ISSN: 1089-7690
    Source: AIP Digital Archive
    Topics: Physics , Chemistry and Pharmacology
    Notes: A new method for decomposing multipoint correlation functions is presented for two-phase suspension materials. The decomposition isolates various aspects of the substructure geometry such as inclusion shape and relative sizes, orientations, and positions of the inclusions. The method can be systematically applied to correlation functions of any order, and it allows them to be calculated directly from a given suspension substructure geometry. First the material properties of the phases are separated from the substructure geometry and this latter is described in terms of the inclusion phase alone. Second the geometric probabilities associated with the inclusion phase are separated into the probabilities associated with the individual inclusions taken singly, and in groups of two or more. The single inclusion probability is given by a geometry problem which is to be solved analytically (or numerically) for a given inclusion shape and orientation. The double inclusion probability, triple inclusion probability, etc., separate into (1) a probability function which depends on inclusion shape, size, and orientation; its calculation is reduced to a geometry problem like that of the single inclusion probability, and (2) inclusion distribution functions which contain configuration statistics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.450973
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 72
    Electronic Resource
    Electronic Resource
    Ordering in the parallel hard hypercube gas (1986)
    College Park, Md. : American Institute of Physics (AIP)
    The Journal of Chemical Physics 85 (1986), S. 3515-3519 
    Details
    ISSN: 1089-7690
    Source: AIP Digital Archive
    Topics: Physics , Chemistry and Pharmacology
    Notes: Ordering in the hard hypercube gas model is discussed. An exact application of density functional theory in the limit of high dimensionality leads to the conclusion that an ordering transition to a simple hypercube lattice occurs at a critical density of hypercubes. The transition is continuous. The structure of the theory suggests a similar transition at finite dimensionality. The critical dynamics below the transition are also computed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.450974
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 73
    Electronic Resource
    Electronic Resource
    Population lifetimes of OH(v=1) and OD(v=1) stretching vibrations of alcohols and silanols in dilute solution (1986)
    College Park, Md. : American Institute of Physics (AIP)
    The Journal of Chemical Physics 85 (1986), S. 5004-5018 
    Details
    ISSN: 1089-7690
    Source: AIP Digital Archive
    Topics: Physics , Chemistry and Pharmacology
    Notes: Picosecond infrared pump–probe experiments determined the vibrational population lifetimes (T1) of the hydroxyl fundamental stretching mode OH(v=1) in 12 alcohols (R3COH) and 8 silanols (R3SiOH) in dilute room temperature CCl4 solutions. T1 for the silanols is in the range 185〈T1〈292 ps, while T1 for the alcohols is much less (T1〈80 ps). The deuterium-exchanged analogs (COD and SiOD) exhibit population relaxation times similar to protonated hydroxyls. An analysis of the vibrational energy levels corresponding to modes involving the four bonds nearest the hydroxyl groups of these molecules is used to qualitatively explain the trends of the observed T1 lifetimes for these systems. Solution T1 lifetimes are also compared to those previously measured for OH(v=1) on the surface of silica and in other condensed-phase, room temperature systems.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.451690
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 74
    Electronic Resource
    Electronic Resource
    Role of binding energies in A− ⋅ B and A ⋅ B− complexes in the kinetics of gas phase electron transfer reactions: A−+B=A+B− involving perfluoro compounds: SF6, C6F11CF3, C6F6 (1986)
    College Park, Md. : American Institute of Physics (AIP)
    The Journal of Chemical Physics 85 (1986), S. 4989-4994 
    Details
    ISSN: 1089-7690
    Source: AIP Digital Archive
    Topics: Physics , Chemistry and Pharmacology
    Notes: Exothermic gas phase electron transfer reactions: A−+B=A+B−, where A and B are polyatomic molecules with positive electron affinities, generally proceed at collision rates. However, reactions involving A=SF6 or perfluorocycloalkanes have rates which decrease with the exothermicity of the reaction, becoming very slow at low exothermicity. Earlier work attributed this behavior to the presence of an energy barrier, due to a large geometry change for A− to A. The reaction coordinate used also involves the bond energies A− ⋅ B and A ⋅ B−. These were measured in the present work. It was found that the bond energy in SF−6 ⋅ B is much larger than in SF6 ⋅ B− . This difference increases the energy barrier very significantly and is thus an additional cause for the slow electron transfer. The bond energies for several other complexes like: Cl− ⋅ B, Cl− ⋅ SF6, Cl− ⋅ perfluorocyloalkanes, and Cl− ⋅ C6F6 were measured. These provide insights into the nature of the bonding involved. The work was performed with a pulsed electron high pressure mass spectrometer.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.451687
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 75
    Electronic Resource
    Electronic Resource
    Reaction rate constant of HO2+O3 measured by detecting HO2 from photofragment fluorescence (1986)
    College Park, Md. : American Institute of Physics (AIP)
    The Journal of Chemical Physics 85 (1986), S. 5027-5034 
    Details
    ISSN: 1089-7690
    Source: AIP Digital Archive
    Topics: Physics , Chemistry and Pharmacology
    Notes: The rate constant for the reaction HO2+O3→OH+2O2 was investigated in a discharge–flow system at room temperature. HO2 was produced from the reaction sequence Cl+CH3OH→CH2OH+HCl and CH2OH+O2→HO2+CH2O. HO2 was detected by the OH(A–X) fluorescence produced from photodissociative excitation of HO2 at 147 nm. A computer modeling of the reaction kinetics occurring in the flow tube was carried out to confirm that contributions from secondary reactions were negligible at low HO2 concentrations. The rate constant was determined from first order decay of HO2 in excess O3. The measured reaction rate constant of HO2+O3 is (1.9±0.3)×10−15 cm3 molecule−1 s−1, which agrees well with published data.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.451692
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 76
    Electronic Resource
    Electronic Resource
    Product quantum state distributions in unimolecular reactions involving highly flexible transition states (1986)
    College Park, Md. : American Institute of Physics (AIP)
    The Journal of Chemical Physics 85 (1986), S. 5035-5040 
    Details
    ISSN: 1089-7690
    Source: AIP Digital Archive
    Topics: Physics , Chemistry and Pharmacology
    Notes: An expression for the distribution of quantum states of the reaction products of unimolecular dissociations is obtained, based on statistical theory. A recently formulated RRKM-type treatment of unimolecular reactions with highly flexible transition states is used to obtain a distribution of quantum states of the products, by introducing an adiabatic approximation for motion from transition state to products. Any impulsive (nonadiabatic) exit channel effects are neglected thereby. Both the final yields of the quantum states of the products and the time evolution of these states are considered. The time evolution of the yield of the products can permit a direct test of non-RRKM effects and, additionally via the long-time component, of other aspects of RRKM theory. The long-time component of the yield of individual quantum states of the products then provides a test of the additional (here, adiabatic) approximation. Such tests are the more definitive the narrower the distribution of initial E's and J's of the dissociating molecule.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.451693
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 77
    Electronic Resource
    Electronic Resource
    Static reaction–diffusion structures in folded slow manifold systems (1986)
    College Park, Md. : American Institute of Physics (AIP)
    The Journal of Chemical Physics 85 (1986), S. 5068-5075 
    Details
    ISSN: 1089-7690
    Source: AIP Digital Archive
    Topics: Physics , Chemistry and Pharmacology
    Notes: Static dissipative structures are obtained analytically for multiple time scale systems with folded slow manifolds. We find that the associated free boundary problem displays much of the richness of the full reaction–diffusion system. For a simple one-dimensional structure the pattern is shown to be linearly stable. Spoke patterns in a disk are calculated exactly. Since one type of static pattern in a disk was shown earlier to unfold into a rotating wave, these patterns are also of interest as the basis for the analysis of a class of multiple arm rotors. In a second special limiting case the patterns are shown to be in the form of narrow "double layers'' in two-dimensional systems. Double layer patterns in a disk are obtained.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.451698
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 78
    Electronic Resource
    Electronic Resource
    Formation mechanism of vibrationally excited O2 molecules in the multiphoton absorption of NO2 (1986)
    College Park, Md. : American Institute of Physics (AIP)
    The Journal of Chemical Physics 85 (1986), S. 5061-5067 
    Details
    ISSN: 1089-7690
    Source: AIP Digital Archive
    Topics: Physics , Chemistry and Pharmacology
    Notes: A pump–probe two-color experiment has been performed to elucidate the formation mechanism of O2 X 3Σ−g in the multiphoton absorption of NO2 over the region 460–540 nm. A probe dye laser was employed to excite O2 X 3Σ−g into the B 3Σ−u state and the UV emission intensity of Schumann–Runge bands was measured under the various experimental conditions. The maximum vibrational level of O2 X 3Σ−g formed is v‘max =24 which corresponds to Evib=30 968 cm−1. The rotational distribution of O2 X 3Σ−g (v‘=24) was almost of Boltzmann with Trot=1300 K at low pressures. The isotopic 1:1 mixture of N16O2 and N18O2 has been photolyzed to test whether the O2 molecules are formed by unimolecular dissociation or through chemical reactions. From the product branching ratio of 16O2:16O18O:18O2 and the maximum vibrational levels observed, the vibrationally excited O2 molecules are concluded to be mainly generated by the chemical reaction of O(1D)+NO2→O2+NO, ΔH=32 000 cm−1. The O(1D) atoms are formed by a sequential three-photon absorption of NO2, where the initial two-photon absorption occurs through the 1 2B2←X˜ 2A1 transition in a cyclic manner and a certain collision-induced process takes place in a dense system of the predissociative states locating in 11 900–19 400 cm−1 above the dissociation threshold of NO(2Π)+O(3P).
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.451697
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 79
    Electronic Resource
    Electronic Resource
    Experimental determination of scattering induced angular momentum alignment in state selected rotational transitions (1986)
    College Park, Md. : American Institute of Physics (AIP)
    The Journal of Chemical Physics 85 (1986), S. 5085-5092 
    Details
    ISSN: 1089-7690
    Source: AIP Digital Archive
    Topics: Physics , Chemistry and Pharmacology
    Notes: Measurements of angular momentum alignment in molecular beam scattering are presented for scattering of Na2 by He, Ne, and Ar. A mechanism for the production of this alignment is discussed, based on mJ conservation for quantization along the momentum transfer vector. The experimental results differ in several aspects from the predictions of this simple mechanism. It is found that the differential cross sections are strongly dependent on mJ. Furthermore, it is found that the principal axis of the orientational distribution does not coincide with the momentum transfer vector. The discrepancy is attributed to a nonstrict mJ conservation in the collision. These experiments are therefore expected to provide a sensitive probe to the nonsudden aspects of molecular scattering.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.451700
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 80
    Electronic Resource
    Electronic Resource
    A Note on the Swift–Connick equations for chemical exchange: The intermediate exchange region (1986)
    College Park, Md. : American Institute of Physics (AIP)
    The Journal of Chemical Physics 85 (1986), S. 3701-3701 
    Details
    ISSN: 1089-7690
    Source: AIP Digital Archive
    Topics: Physics , Chemistry and Pharmacology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.450939
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 81
    Electronic Resource
    Electronic Resource
    The singlet–triplet energy separation in silylene (1986)
    College Park, Md. : American Institute of Physics (AIP)
    The Journal of Chemical Physics 85 (1986), S. 5117-5119 
    Details
    ISSN: 1089-7690
    Source: AIP Digital Archive
    Topics: Physics , Chemistry and Pharmacology
    Notes: MCSCF calculations followed by large scale configuration interaction, comparable with the best done for isovalent methylene, give a singlet–triplet splitting in silylene of 21.0±1 kcal/mol. The singlet is the lower energy state. Structural parameters for the as yet unobserved triplet are re =1.48±0.005 A(ring) and θe =118.5±1°.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.451704
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 82
    Electronic Resource
    Electronic Resource
    Fluorescence of cyclohexane vapor: Pressure dependence and quenching studies (1986)
    College Park, Md. : American Institute of Physics (AIP)
    The Journal of Chemical Physics 85 (1986), S. 2445-2449 
    Details
    ISSN: 1089-7690
    Source: AIP Digital Archive
    Topics: Physics , Chemistry and Pharmacology
    Notes: The pressure dependence of the fluorescence lifetime of cyclohexane vapor excited at wavelengths between 168.5 and 175.0 nm has been investigated. Due to the unusual dependence of the lifetime on cyclohexane pressure, a simple Stern–Volmer type of extrapolation cannot be used to obtain the collisionless lifetime at any of the excitation energies employed. Also, fluorescence decay curves fit a single-exponential function only under certain conditions of pressure and excitation wavelength. The rate constants for quenching of the excited state(s) by O2 at excitation wavelengths of 172.0 and 169.5 nm are (6.1±0.1)×10−10 and (7.9±1.4)×10−10 cm3 molecule−1 s−1, respectively. The difference between these rate constants is not significantly larger than the experimental uncertainty. At 172.0 nm, the rate constant for quenching by Xe is (7.1±0.3)×10−12 cm3 molecule−1 s−1. At this same excitation wavelength, quenching by He, Ar, and N2 is extremely small.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.451103
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 83
    Electronic Resource
    Electronic Resource
    NMR spectra of dilute spins under slow sample-spinning and homonuclear decoupling (1986)
    College Park, Md. : American Institute of Physics (AIP)
    The Journal of Chemical Physics 85 (1986), S. 2458-2462 
    Details
    ISSN: 1089-7690
    Source: AIP Digital Archive
    Topics: Physics , Chemistry and Pharmacology
    Notes: Dilute-spin spectra under decoupling between abundant spins and slow sample spinning at general angles are discussed, and experimentally observed with an example of calcium formate. Spectra obtained at off-magic angles break up into a train of characteristic patterns different in shape from each other. The center pattern was found to be especially sensitive to the mutual orientation between the chemical shift and dipolar coupling tensors. Each sideband observed at the magic angle shows splitting due to the 13C–1H indirect coupling. The absolute sign of the coupling constant is determined to be positive from the J-split sideband pattern.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.451054
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 84
    Electronic Resource
    Electronic Resource
    Spin uncoupling in the 6s Rydberg states of methyl iodide. Rotational subband structure in one-photon absorption (1986)
    College Park, Md. : American Institute of Physics (AIP)
    The Journal of Chemical Physics 85 (1986), S. 2483-2488 
    Details
    ISSN: 1089-7690
    Source: AIP Digital Archive
    Topics: Physics , Chemistry and Pharmacology
    Notes: Molecular constants of electronic states, all origins as well as some vibronic bands, derived from the lowest-energy Rydberg configuration of methyl iodide, are reported. Values of the internal angular momentum parameter ζeff, which is a measure of the strength of Coriolis and vibronic coupling, indicate that the spin of the Rydberg electron is effectively uncoupled from the molecular axis in the pure electronic states and that dynamic interactions between electronic, rotational, and vibrational motions completely quench the internal angular momentum in some vibronic levels. It is concluded that the parameters ζeff, as obtained from one-photon absorption spectra, are approximately those of the alternate levels, 2E3/2 and 2E1/2, of the CH3I+ ion-core ground configuration X˜.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.451817
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 85
    Electronic Resource
    Electronic Resource
    Rydberg states of NO trapped in rare gas matrices (1986)
    College Park, Md. : American Institute of Physics (AIP)
    The Journal of Chemical Physics 85 (1986), S. 2472-2482 
    Details
    ISSN: 1089-7690
    Source: AIP Digital Archive
    Topics: Physics , Chemistry and Pharmacology
    Notes: Several new progressions consisting of broadbands have been observed in the absorption spectra of NO trapped in rare gas matrices. They are identified as the blue shifted transitions to the n=3 (A 2Σ+,C 2Π,D 2Σ+) and n=4 (E 2Σ+,K 2Π,M 2Σ+) Rydberg states of NO in Ne matrices and to the n=3 Rydberg states in Ar, Kr, and Xe matrices. Linewidths (50 to 180 meV) and matrix shifts (0.3 to 1.2 eV) decrease from neon to xenon matrices. For each matrix, the shifts decrease according to the symmetry of the excited state orbital, in the sequence sσ–pσ–pπ. An attempt to apply the quantum defect formula with values, for the Rydberg constant and the ionization potential of the matrix isolated molecule taken from literature, fails to describe the vertical transition energies of n=3 and n=4 states in neon matrices. On the other hand, using the adiabatic energies of 3sσ and 4sσ states to generate a series shows that the vertical transitions of n≥5 states lie in the ionization continuum. This could explain the nonobservation of n〉4 states in Ne matrices. In the heavier matrices, this model predicts n=4 states but their existence is not borne out by experiment. The Wannier model also fails to describe these transitions.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.451056
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 86
    Electronic Resource
    Electronic Resource
    Complex dynamic NMR spectra in the fast exchange limit (1986)
    College Park, Md. : American Institute of Physics (AIP)
    The Journal of Chemical Physics 85 (1986), S. 2516-2527 
    Details
    ISSN: 1089-7690
    Source: AIP Digital Archive
    Topics: Physics , Chemistry and Pharmacology
    Notes: Symmetries in Liouville space are used to construct analytical relaxation equations for the density matrix of chemically exchanging systems in the fast exchange limit. The method is particularly useful when a symmetry group for the exchange superoperator can be found. The method is applied to the proton NMR of molecules which are dissolved in liquid crystals, and which undergo isomerization reactions, such as ring inversion and bond shift rearrangement. The results are compared with exact calculations in order to check the range of validity of the fast exchange approximation. For completeness the slow exchange approximation equations are also compared with the exact procedure. It is found that the approximate equation in both limits can faithfully reproduce the NMR spectra over most of the dynamic range and often without a gap. The approximate equations significantly shorten the computation time, making it possible to simulate dynamic line shape for as big a molecule as cyclohexane.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.451060
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 87
    Electronic Resource
    Electronic Resource
    van der Waals potentials from the infrared spectra of rare gas–HF complexes (1986)
    College Park, Md. : American Institute of Physics (AIP)
    The Journal of Chemical Physics 85 (1986), S. 2502-2515 
    Details
    ISSN: 1089-7690
    Source: AIP Digital Archive
    Topics: Physics , Chemistry and Pharmacology
    Notes: High-resolution infrared spectra of the Ar–HF, Kr–HF, and Xe–HF van der Waals molecules have been recorded in the vicinity of the H–F stretching fundamentals, ν1, under thermal equilibrium conditions at T(approximately-equal-to)211 K with a tunable difference-frequency laser. Rotational structure has been observed up to or approaching rotational predissociation, permitting us to model the effective radial van der Waals potentials for these complexes. These potentials provide good estimates for the binding energies, D0, and the van der Waals stretching frequencies, ν3, in the ground (v1=0) and excited (v1=1) states of the molecules. For v1=0 in Ar–HF, Kr–HF, and Xe–HF, we find D0=102, 133, and 181 cm−1 and ν3=39.2, 41.1, and 43.4 cm−1, respectively. The ν3 modes characterized by the model potentials aid in the assignment of the ν1+ν3−ν3 hot bands observed in our spectra. The band centers for the ν1 fundamentals are all down shifted in frequency from the isolated HF monomer by Δν=−9.654, −17.518, and −29.185 cm−1 for the Ar, Kr, and Xe complexes, respectively, indicating that the van der Waals bonds are some 10% to 15% stronger in the excited vibrational state. This increased vibrational attraction also results in a contraction of the van der Waals radial coordinate manifest in the larger rotational constants observed for ν1; ΔB/B0=+0.35%, +1.00%, and +1.75% for Ar–, Kr–, and Xe–HF. We have also observed the Q branch of the ν1+ν2 stretch–bend combination band in Ar–HF some 70.2 cm−1 above the ν1 fundamental with a large negative ΔB/B0=−2.00% implying a strong anisotropy in the potential.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.451059
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 88
    Electronic Resource
    Electronic Resource
    Pulsed Ge+n microcluster concentration spectra (1986)
    College Park, Md. : American Institute of Physics (AIP)
    The Journal of Chemical Physics 85 (1986), S. 5246-5250 
    Details
    ISSN: 1089-7690
    Source: AIP Digital Archive
    Topics: Physics , Chemistry and Pharmacology
    Notes: Bloomfield, Geusic, Freeman, and Brown have used the Smalley synchronized laser and supersonic quenching carrier gas pulsed method to obtain spectra for Ge+n similar to pulsed spectra obtained previously for Si+n. Their data are presented, compared to data obtained with electron beam ionization, and discussed extensively in order to separate effects due to cluster stabilization energies, growth kinetics, and ionization fragmentation. Differences in chemical bonding and growth kinetics between Si+n and Ge+n microclusters are discussed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.451665
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 89
    Electronic Resource
    Electronic Resource
    Theory of translation–rotation coupling in sodium azide (1986)
    College Park, Md. : American Institute of Physics (AIP)
    The Journal of Chemical Physics 85 (1986), S. 5251-5261 
    Details
    ISSN: 1089-7690
    Source: AIP Digital Archive
    Topics: Physics , Chemistry and Pharmacology
    Notes: A microscopic theory of softening of elastic modulii in β-NaN3, the high temperature phase of solid sodium azide, is given. The softening of the elastic modulii occurs due to coupling of the rotational degrees of freedom of an azide ion to the translational degrees of freedom of the neighboring ions. The softening of elastic modulus C44 is found to be more pronounced than that of C66, while C14 is found to be independent of temperature. The contribution of fourth order angular momentum terms l=4 to softening are found to be negligible for C44, but are appreciable for C66. A good fit to the Brillouin data of Kushida and Terhune (Ref. 1) is obtained by reducing both the electric charge on the end N atoms of N−3 and the strength of the Born–Mayer repulsive interaction from their values available in the literature. The experimental value of the extrapolated transition temperature Texpc =18 °C agrees well with the calculated transition temperature of Tc =24 °C.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.451666
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 90
    Electronic Resource
    Electronic Resource
    Spatial correlation functions from computer simulations (1986)
    College Park, Md. : American Institute of Physics (AIP)
    The Journal of Chemical Physics 85 (1986), S. 5262-5268 
    Details
    ISSN: 1089-7690
    Source: AIP Digital Archive
    Topics: Physics , Chemistry and Pharmacology
    Notes: A method is presented for the computation of the surface–surface and surface–void spatial correlation functions from computer simulations of heterogeneous media. The method is illustrated with Monte Carlo simulations of penetrable spheres (for which exact analytical solutions are known) and of impenetrable spheres. Doi's bound on the fluid permeability of a dispersion of impenetrable spheres is calculated.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.451667
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 91
    Electronic Resource
    Electronic Resource
    Influence of ligands on the x-ray absorption near-edge structure of palladium(II) complex compounds (1986)
    College Park, Md. : American Institute of Physics (AIP)
    The Journal of Chemical Physics 85 (1986), S. 5269-5272 
    Details
    ISSN: 1089-7690
    Source: AIP Digital Archive
    Topics: Physics , Chemistry and Pharmacology
    Notes: The palladium LIII absorption and chlorine K absorption spectra from [Pd(NH3)4]Cl2 ⋅ H2O and Pd(OCOCH3)2 have been reported for the first time and discussed in connection with the Pd LIII absorption and Cl K absorption spectra of K2PdCl4, reported previously. The influence of the ligands Cl−, OCOCH−3, and NH3 has been observed in the pallaldium LIII absorption spectra of these compounds. The observed chemical shift of a strong "white line'' at the Pd LIII absorption threshold can be explained in terms of the spectrochemical series of the ligands. An intense white line disappears at the Cl K absorption threshold of [Pd(NH3)4]Cl2 ⋅ H2O in contrast to the Cl K absorption spectrum of K2PdCl4.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.451668
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 92
    Electronic Resource
    Electronic Resource
    Classical and semiclassical aspects of dissipative molecular processes: Radiative and nonradiative vibrational relaxation in polyatomic molecules (1986)
    College Park, Md. : American Institute of Physics (AIP)
    The Journal of Chemical Physics 85 (1986), S. 2581-2590 
    Details
    ISSN: 1089-7690
    Source: AIP Digital Archive
    Topics: Physics , Chemistry and Pharmacology
    Notes: The time dependence of spontaneous emission from isolated, highly vibrationally excited molecules is studied from the point of view of the classical and semiclassical mechanics of dissipatively perturbed Hamiltonian systems. A correlation function expression for the time-dependent emission spectrum serves as a starting point for quasiclassical approximations. These in turn lead to an investigation of the classical dynamics of model molecular systems in which small, energy-nonconserving terms have been added to Hamilton's equations. Numerical calculations show rich dynamical behavior which can be qualitatively understood in terms of the resonance structure of the unperturbed system. For example, trajectories tend to be captured by zones of nonlinear resonance. This "mode locking'' produces a characteristic cleanup of an emission spectrum that otherwise is rather congested at these energies. The close connection between spectra and dynamics suggests that the classical dynamics of dissipatively perturbed systems may provide a useful language for interpreting radiative and condensed-phase vibrational relaxation, and possibly some types of intramolecular relaxation phenomena as well.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.451065
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 93
    Electronic Resource
    Electronic Resource
    State selective population of H2(v″=1, J″=1) and D2(v″=1, J″=2) and rotational relaxation in collisions with H2, D2, and He (1986)
    College Park, Md. : American Institute of Physics (AIP)
    The Journal of Chemical Physics 85 (1986), S. 2599-2608 
    Details
    ISSN: 1089-7690
    Source: AIP Digital Archive
    Topics: Physics , Chemistry and Pharmacology
    Notes: Single rotational states were populated in vibrationally excited hydrogen by stimulated Raman pumping. The population in H2 X 1∑+g(v″=0,1) and D2 X 1∑+g(v″=0,1) was probed state selectively by tunable vacuum ultraviolet (VUV) laser radiation around λ=110 nm, and the fluorescence induced when exciting the hydrogen molecules in the (0–0), (1–0), (2–0), (3–1), and (4–1) Lyman bands of the (B 1∑+u←X 1∑+g) transition monitored. From a comparison of line heights, the stimulated Raman pumping efficiency is estimated to be 30%–50% in the focal volume. Rotational transitions in X 1∑+g(v″=1) were induced in collisions with H2, D2, and He. State-to-state rotational relaxation rates were measured for the (J″=1→J″=3) transition in H2(v″=1) and for the (J″=2→J″=0,4) transitions in D2(v″=1). These rates were found to be generally higher than the corresponding previously determined ones in ground state hydrogen, in qualitative accord with recent theoretical calculations. A comparison with available theoretical state-to-state cross sections shows that the rates obtained with these cross sections are generally lower than the relaxation rates directly measured in this work.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.451068
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 94
    Electronic Resource
    Electronic Resource
    Kinetic oscillations in the catalytic CO oxidation on Pt(100): Computer simulations (1986)
    College Park, Md. : American Institute of Physics (AIP)
    The Journal of Chemical Physics 85 (1986), S. 5328-5336 
    Details
    ISSN: 1089-7690
    Source: AIP Digital Archive
    Topics: Physics , Chemistry and Pharmacology
    Notes: The previously observed phenomena of temporal and spatial self-organization during the catalytic oxidation of CO on a Pt(100) surface were computer simulated by use of the cellular automaton technique. The underlying model is footed on the knowledge about the individual reaction steps (adsorption, desorption, surface structural transformation, etc.), which in turn formed the basis of a previous theoretical treatment in terms of the formulation and solution of a set of coupled differential equations. The present result nicely show the formation and propagation of two-dimensional patterns, and they reproduce qualitatively well all the experimental observations. The development of macroscopic patterns even with an a priori perfectly homogeneous surface is a particularly interesting effect.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.451676
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 95
    Electronic Resource
    Electronic Resource
    Dynamics and spectroscopy of near threshold nonadiabatic resonances in photodissociation to open shell atoms: CH+ a model system (1986)
    College Park, Md. : American Institute of Physics (AIP)
    The Journal of Chemical Physics 85 (1986), S. 2699-2717 
    Details
    ISSN: 1089-7690
    Source: AIP Digital Archive
    Topics: Physics , Chemistry and Pharmacology
    Notes: Close-coupled theoretical calculations of the near threshold photodissociation of CH+ exhibit a wealth of structure. This structure arises because of the presence of nonadiabatic interactions which always exist and which are significant at large distances when molecules dissociate to open shell atoms. Detailed analysis of the calculated photodissociation spectrum, using an extensive set of theoretical diagnostics, displays a series of systematic trends in the spectrum which enable the assignment of resonance features in this extremely complicated spectrum. The results show how general spectroscopic principles may be used in analyzing this type of complicated structure, and our calculations provide general insight into the experimental data for the photodissociation of CH+. The theoretical calculations also indicate how additional assistance with analyzing experimental data can come from measurements of fragment kinetic energy, angular distributions, and polarizations.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.451027
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 96
    Electronic Resource
    Electronic Resource
    Quantum studies of inelastic collisions of O2(X 3Σ−g) with He: Polarization effects and collisional propensity rules (1986)
    College Park, Md. : American Institute of Physics (AIP)
    The Journal of Chemical Physics 85 (1986), S. 2726-2737 
    Details
    ISSN: 1089-7690
    Source: AIP Digital Archive
    Topics: Physics , Chemistry and Pharmacology
    Notes: We investigate rotationally inelastic cross sections of O2(X 3Σ−g) with He at a collision energy of 27 meV. Theoretical cross sections obtained from close-coupled (CC) calculations are compared with results from the infinite-order sudden (IOS) approximation. Both the CC and IOS fine-structure state-resolved cross sections exhibit a strong ΔN=ΔJ Fi conserving collisional propensity. An analysis of the general expression for state-resolved cross sections in terms of spin-independent tensor opacities clearly establishes, without the introduction of dynamical approximations, the direct connection between this propensity rule and the collisional propensity for the conservation of the orientation of the nuclear rotational angular momentum vector N. In the low-N limit, Fi changing O2–He collisions are much more strongly depolarizing than collisions that conserve the Fi symmetry level. This enhanced collisional depolarization of an initial distribution of the total molecular angular momentum vector J is related to the collisional reorientation of N that must occur in Fi changing transitions.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.451029
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 97
    Electronic Resource
    Electronic Resource
    Double differential cross sections for alkali–Hg collisions in the 100 eV range. I. Time-of-flight measurements (1986)
    College Park, Md. : American Institute of Physics (AIP)
    The Journal of Chemical Physics 85 (1986), S. 2738-2750 
    Details
    ISSN: 1089-7690
    Source: AIP Digital Archive
    Topics: Physics , Chemistry and Pharmacology
    Notes: Differential cross sections with energy analysis have been measured for Na, K, and Cs atoms scattered from Hg for collision energies between 36 and 200 eV. The energy analysis is performed with standard time-of-flight technique yielding the cross sections for elastic scattering and scattering with excitation of the lowest alkali P state. The cross sections for all other excited states are found to be smaller by several orders of magnitude. A new semiempirical potential model is described which has been used to interpret the experimental results. Parameters for the best fit to our results are given in this two-state model for K and Cs. For Na we can only give a coarse estimate. Some serious failures of the semiclassical theory have been discovered, which have lead us to the use of quantum mechanical calculations.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.451030
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 98
    Electronic Resource
    Electronic Resource
    g˜-tensor calculation for FeIII triads: Application to the 3Fe clusters in iron–sulfur proteins (1986)
    College Park, Md. : American Institute of Physics (AIP)
    The Journal of Chemical Physics 85 (1986), S. 2774-2778 
    Details
    ISSN: 1089-7690
    Source: AIP Digital Archive
    Topics: Physics , Chemistry and Pharmacology
    Notes: The g˜ tensor of a triad of high spin FeIII ions coupled by antiferromagnetic exchange interactions, is calculated in the case where the fine structure terms are not negligible compared to the exchange parameters. Using some simplifying assumptions concerning the relative orientations of the magnetic axes, we obtain the expressions of the g components in closed form. A simple "g strain'' model based on these expressions is used to simulate the EPR spectra given by the 3Fe clusters of four different iron sulfur proteins. In each case, a good simulation is only observed if the three exchange parameters are nearly equal, and of the order of −20 cm−1. These conclusions are in good agreement with our earlier estimations which were obtained by an independent method [J. P. Gayda, P. Bertrand, F-X. Theodule, and J. J. G. Moura, J. Chem. Phys. 77, 3387 (1982)].
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.451033
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 99
    Electronic Resource
    Electronic Resource
    Monte Carlo simulation on the solvent structure of biopolymers for the study of the effect of hydration on their energy band structure (1986)
    College Park, Md. : American Institute of Physics (AIP)
    The Journal of Chemical Physics 85 (1986), S. 5365-5369 
    Details
    ISSN: 1089-7690
    Source: AIP Digital Archive
    Topics: Physics , Chemistry and Pharmacology
    Notes: The complete solvent structure of a polyalanine fragment in the β-pleated sheet conformation with a repeat unit of two alanine molecules has been determined. In this Monte Carlo simulation, 97 water molecules have been included, their interaction energies and the number of water molecules in the different regions of alanine have been calculated. A water cluster as hydration shell of polyalanine in the β-pleated sheet conformation has been chosen. Then for polyalanine, ab initio crystal orbital calculations have been performed to investigate the effect of the hydration shell on its band structure. The presence of the water molecules caused some band shifts. The width of the conduction band increased by 0.63 eV that is it became more than twice as wide as without the hydration shell. The forbidden bandwidth decreased by nearly 0.8 eV.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.451680
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 100
    Electronic Resource
    Electronic Resource
    Direct measurement of intermolecular forces between a polymer layer and mica (1986)
    College Park, Md. : American Institute of Physics (AIP)
    The Journal of Chemical Physics 85 (1986), S. 5370-5371 
    Details
    ISSN: 1089-7690
    Source: AIP Digital Archive
    Topics: Physics , Chemistry and Pharmacology
    Notes: We report here the first direct measurement of intermolecular forces between a polymer layer and a solid surface. When solid surfaces bearing adsorbed polymer approach one another, interactions develop that may be categorized as polymer–polymer and polymer–solid (and a negligible contribution of solid–solid interactions at the large solid–solid separations imposed by adsorbed polymer). Direct measurements of the forces between polymer layers adsorbed on mica have been made recently with apparatus of the type developed by Israelachvili. Attractive forces are attributed to a combination of osmotic (polymer–polymer) and bridging (polymer–solid) interactions. Bridging occurs if macromolecules adsorbed one one surface can reach a second surface. In the work presented here, poly(α-methylstyrene) (PαMS) adsorbed on one mica sheet was brought into contact in cyclohexane with a bare mica sheet. Adhesion was measured as a function of separation and contact time and found to be more than 20 times greater than between two polymer–coated surfaces under otherwise identical conditions. This direct measurement of molecular forces between dissimilar surfaces enables estimation of the PαMS segmental sticking energy on mica in cyclohexane as (1)/(3) kT.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.451681
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
Close ⊗
This website uses cookies and the analysis tool Matomo. More information can be found here...