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
  • 1
    Electronic Resource
    Electronic Resource
    Cavity ringdown laser absorption spectroscopy and time-of-flight mass spectroscopy of jet-cooled silver silicides (1995)
    College Park, Md. : American Institute of Physics (AIP)
    The Journal of Chemical Physics 103 (1995), S. 113-120 
    Details
    ISSN: 1089-7690
    Source: AIP Digital Archive
    Topics: Physics , Chemistry and Pharmacology
    Notes: The cavity ringdown technique has been employed for the first spectroscopic characterization of the AgSi molecule, which is generated in a pulsed laser vaporization plasma reactor. A total of 20 rovibronic bands between 365 and 385 nm have been measured and analyzed to yield molecular properties for the X, B, and C 2Σ states of AgSi. A time-of-flight mass spectrometer simultaneously monitors species produced in the molecular beam and has provided the first direct evidence for the existence of polyatomic silver silicides. Comparison of the AgSi data to our recent results for the CuSi diatom reveals very similar chemical bonding in the two coinage metal silicides, apparently dominated by covalent interactions. © 1995 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.469649
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 2
    Electronic Resource
    Electronic Resource
    Cavity ringdown laser absorption spectroscopy and time-of-flight mass spectroscopy of jet-cooled copper silicides (1995)
    College Park, Md. : American Institute of Physics (AIP)
    The Journal of Chemical Physics 102 (1995), S. 5190-5199 
    Details
    ISSN: 1089-7690
    Source: AIP Digital Archive
    Topics: Physics , Chemistry and Pharmacology
    Notes: The cavity ringdown technique has been implemented for electronic spectroscopy of jet-cooled CuSi produced in a pulsed UV laser vaporization plasma reactor. A time-of-flight mass spectrometer is used to simultaneously monitor species produced in the supersonic expansion and allows correlation studies to be performed. Seven rotationally resolved vibronic bands have been measured near 400 nm, yielding spectroscopic constants for the 2Σ ground and excited states. Vibronic isotope shifts, together with rotational line positions, permit the unambiguous determination of the spectral carrier and vibronic assignment. Since no ab initio studies for the CuSi molecule exist, a comparison to ab initio studies of the related NiSi molecule is presented. Time-of-flight mass spectrometric measurements indicate the facile formation of CuxSiy clusters containing multiple copper atoms, in contrast to earlier mass spectrometric work on transition metal silicides. © 1995 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.469244
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 3
    Electronic Resource
    Electronic Resource
    Fully coupled six-dimensional calculations of the water dimer vibration-rotation-tunneling states with split Wigner pseudospectral approach. II. Improvements and tests of additional potentials (1999)
    College Park, Md. : American Institute of Physics (AIP)
    The Journal of Chemical Physics 110 (1999), S. 6306-6318 
    Details
    ISSN: 1089-7690
    Source: AIP Digital Archive
    Topics: Physics , Chemistry and Pharmacology
    Notes: The SWPS method is improved by the addition of H.E.G. contractions for generating a more compact basis. An error in the definition of the internal fragment axis system used in our previous calculation is described and corrected. Fully coupled 6D (rigid monomers) VRT states are computed for several new water dimer potential surfaces and compared with experiment and our earlier SWPS results. This work sets the stage for refinement of such potential surfaces via regression analysis of VRT spectroscopic data. © 1999 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.478535
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 4
    Electronic Resource
    Electronic Resource
    The far-infrared vibration–rotation–tunneling spectrum of the water tetramer-d8 (1996)
    College Park, Md. : American Institute of Physics (AIP)
    The Journal of Chemical Physics 105 (1996), S. 6634-6644 
    Details
    ISSN: 1089-7690
    Source: AIP Digital Archive
    Topics: Physics , Chemistry and Pharmacology
    Notes: The far-infrared vibration–rotation–tunneling spectrum of (D2O)4 has been measured in the spectral region near 2.04 THz. Observation of additional transition doublets with a constant 5.6 MHz spacing in a parallel (c-type) spectrum extends the first detailed study of this cluster [Science 271, 59 (1996)]. Three possibilities are explored for the origin of this small splitting: tunneling between degenerate equilibrium structures via facile torsional motions analogous to those observed in the water trimer, tunneling between nondegenerate structural frameworks, and tunneling made feasible only through excitation of a specific vibrational coordinate. The degenerate tunneling scheme best accounts for the spectral features, although the precise dynamics responsible for the observed spectral features cannot be uniquely established from the present data. A further doubling of spectral features, observed only in the K=2 manifold of transitions for J≥3, is symmetric about the unperturbed symmetric top energy levels and shows an approximate J2 dependence of the spacing. The origin of these additional splittings, which are shown to be present in both upper and lower vibrational states of the spectrum, is likely to be due to an interaction between overall rotational angular momentum and the type of internal motion ("pseudorotation'') that gives rise to a manifold of low energy states in water trimer. The measured interoxygen separations in (D2O)n (n=2,3,4,5) are analyzed in order to quantify the contribution of many-body forces in bulk water. An exponential contraction of this property toward the value found in ordered ice is observed. © 1996 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.471977
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 5
    Electronic Resource
    Electronic Resource
    Infrared cavity ringdown spectroscopy of water clusters: O–D stretching bands (1998)
    College Park, Md. : American Institute of Physics (AIP)
    The Journal of Chemical Physics 109 (1998), S. 10201-10206 
    Details
    ISSN: 1089-7690
    Source: AIP Digital Archive
    Topics: Physics , Chemistry and Pharmacology
    Notes: The infrared O–D stretching spectrum of fully deuterated jet-cooled water clusters is reported. Sequential red-shifts in the single donor O–D stretches, which characterize the cooperative effects in the hydrogen bond network, were accurately measured for clusters up to (D2O)8. Detailed comparisons with corresponding data obtained for (H2O)n clusters are presented. Additionally, rotational analyses of two D2O dimer bands are presented. These measurements were made possible by the advent of infrared cavity ringdown laser absorption spectroscopy (IR-CRLAS) using Raman-shifted pulsed dye lasers, which creates many new opportunities for gas phase IR spectroscopy. © 1998 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.477714
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 6
    Electronic Resource
    Electronic Resource
    Tunneling dynamics, symmetry, and far-infrared spectrum of the rotating water trimer. II. Calculations and experiments (1996)
    College Park, Md. : American Institute of Physics (AIP)
    The Journal of Chemical Physics 105 (1996), S. 8051-8063 
    Details
    ISSN: 1089-7690
    Source: AIP Digital Archive
    Topics: Physics , Chemistry and Pharmacology
    Notes: With the Hamiltonian derived in the preceding paper and the ab initio potentials of T. Bürgi, S. Graf, S. Leutwyler, and W. Klopper [J. Chem. Phys. 103, 1077 (1995)] and of J. G. C. M. van Duijneveldt-van de Rijdt and F. B. van Duijneveldt [Chem. Phys. Lett. 237, 560 (1995)], we calculate the pseudo-rotation tunneling levels in a rotating water trimer. The internal motions are treated by a three-dimensional discrete variable representation and the Coriolis coupling with the overall rotation is included. Also the effects of donor tunneling are included, by introducing semi-empirical coupling matrix elements. New experimental data are presented for the c-type band at 87.1 cm−1 in (H2O)3, which show that specific levels in the donor tunneling quartets of this band are further split into doublets. With the results of our quantitative calculations and the model of the preceding paper we can understand the mechanisms of all the splittings observed in the earlier high-resolution spectra of (H2O)3 and (D2O)3, as well as these new splittings, in terms of pseudo-rotation tunneling, donor tunneling and Coriolis coupling. An unambiguous assignment is given of all the bands observed and analyzed. The ab initio potential of the Van Duijneveldts yields accurate energies of the lower pseudo-rotation levels, the potential of Bürgi et al. performs better for the higher levels. With our analysis we can deduce from the spectra that donor tunneling involves inversion of the trimer. © 1996 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.472661
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 7
    Electronic Resource
    Electronic Resource
    Cavity ringdown laser absorption spectroscopy and time-of-flight mass spectroscopy of jet cooled platinum silicides (1996)
    College Park, Md. : American Institute of Physics (AIP)
    The Journal of Chemical Physics 104 (1996), S. 2782-2788 
    Details
    ISSN: 1089-7690
    Source: AIP Digital Archive
    Topics: Physics , Chemistry and Pharmacology
    Notes: The cavity ringdown technique (CRLAS) has been employed to measure the gas phase absorption spectrum of the platinum silicide molecule in the 350 nm region. All nine of the measured rovibronic bands are assigned to a single 1Σ–1Σ electronic transition, with a ground state vibrational frequency of ωe″=549.0(3) cm−1, and a bond length of r0″=2.069(1) A(ring). The results of this study are compared with experimental data for the coinage metal silicides. Additionally, time-of-flight mass spectrometric results indicate that a variety of polyatomic metal silicides are formed in our molecular jet expansion. © 1996 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.471101
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 8
    Electronic Resource
    Electronic Resource
    Vibration–rotation–tunneling dynamics calculations for the four-dimensional (HCl)2 system: A test of approximate models (1995)
    College Park, Md. : American Institute of Physics (AIP)
    The Journal of Chemical Physics 103 (1995), S. 921-932 
    Details
    ISSN: 1089-7690
    Source: AIP Digital Archive
    Topics: Physics , Chemistry and Pharmacology
    Notes: Several commonly used approximate methods for the calculation of vibration–rotation–tunneling spectra for (HCl)2 are described. These range from one-dimensional models to an exact coupled four-dimensional treatment of the intermolecular dynamics. Two different potential surfaces were employed—an ab initio and our ES1 experimental surface (determined by imbedding the four-dimensional calculation outlined here in a least-squares loop to fit the experimental data, which is described in the accompanying paper [J. Chem. Phys. 103, 933 (1995)]. The most important conclusion deduced from this work is that the validity of the various approximate models is extremely system specific. All of the approximate methods addressed in this paper were found to be sensitive to the approximate separability of the radial and angular degrees of freedom, wherein exists the primary difference between the two potentials. Of particular importance, the commonly used reversed adiabatic angular approximation was found to be very sensitive to the choice for fixed R; an improper choice would lead to results very much different from the fully coupled results and perhaps to false conclusions concerning the intermolecular potential energy surface. © 1995 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.469793
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 9
    Electronic Resource
    Electronic Resource
    Determination of the intermolecular potential energy surface for (HCl)2 from vibration–rotation–tunneling spectra (1995)
    College Park, Md. : American Institute of Physics (AIP)
    The Journal of Chemical Physics 103 (1995), S. 933-949 
    Details
    ISSN: 1089-7690
    Source: AIP Digital Archive
    Topics: Physics , Chemistry and Pharmacology
    Notes: An accurate and detailed semiempirical intermolecular potential energy surface for (HCl)2 has been determined by a direct nonlinear least-squares fit to 33 microwave, far-infrared and near-infrared spectroscopic quantities using the analytical potential model of Bunker et al. [J. Mol. Spectrosc. 146, 200 (1991)] and a rigorous four-dimensional dynamical method (described in the accompanying paper). The global minimum (De=−692 cm−1) is located near the hydrogen-bonded L-shaped geometry (R=3.746 A(ring), θ1=9°, θ2=89.8°, and φ=180°). The marked influence of anisotropic repulsive forces is evidenced in the radial dependence of the donor–acceptor interchange tunneling pathway. The minimum energy pathway in this low barrier (48 cm−1) process involves a contraction of 0.1 A(ring) in the center of mass distance (R) at the C2h symmetry barrier position. The new surface is much more accurate than either the ab initio formulation of Bunker et al. or a previous semiempirical surface [J. Chem. Phys. 78, 6841 (1983)]. © 1995 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.469794
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 10
    Electronic Resource
    Electronic Resource
    Infrared cavity ringdown spectroscopy of methanol clusters: Single donor hydrogen bonding (1999)
    College Park, Md. : American Institute of Physics (AIP)
    The Journal of Chemical Physics 110 (1999), S. 4258-4267 
    Details
    ISSN: 1089-7690
    Source: AIP Digital Archive
    Topics: Physics , Chemistry and Pharmacology
    Notes: Infrared cavity ringdown laser absorption spectroscopy has been used to study the O–H stretching vibrations of jet-cooled methanol clusters in direct absorption. Rovibrational bands for (CH3OH)2, (CH3OH)3, and (CH3OH)4 have been measured. Both bonded and free O–H stretches were measured for the dimer, indicating that its structure is linear. Five bands were assigned to the methanol trimer, indicating the presence of a second cyclic isomer in the molecular beam. A detailed study of the free O–H stretching region shows that methanol clusters larger than dimer must exist in cyclic ring configurations. In order to facilitate spectral assignment, harmonic frequencies and infrared intensities were calculated for the methanol monomer, dimer, and trimer with second order Møller–Plesset perturbation theory. Using the theoretical infrared intensities and measured vibrational band absorptions, absolute cluster concentrations were calculated. Results agree with previous experimental and theoretical work. © 1999 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.478309
    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...