ALBERT — All Library Books, journals and Electronic Records Telegrafenberg

11

Digitale Medien

Radiative lifetimes of HBr+ and DBr+ (2Π1/2, v=0, 1) (1994)

Jullien, S. ; Lemaire, J. ; Fenistein, S. ; [weitere]

College Park, Md. : American Institute of Physics (AIP)

The Journal of Chemical Physics 101 (1994), S. 265-270

zur Merkliste hinzufügen auf der Merkliste

Details

ISSN: 1089-7690

Quelle: AIP Digital Archive

Thema: Physik , Chemie und Pharmazie

Notizen: Radiative lifetimes of HBr+ and DBr+(2Π1/2, v=0, 1) have been determined using the monitor ion technique in a triple cell ICR spectrometer with Fourier transform detection. The experimental lifetimes corresponding to the vibrational transition v=1→0 are 10.2±1 ms and 56+12−11 ms for HBr+ and DBr+, respectively. The lifetimes calculated by a coupled electron pair approximation (CEPA) method similar to the method used previously for HF+ and HCl+ are 8.8 ms for HBr+ and 35.8 ms for DBr+, in rather good agreement with the experimental results. A comparison with previous experimental and theoretical results on hydrogen halides shows a shortening of the lifetime between the neutrals and the corresponding ions and a lengthening with isotopic substitution (H by D) as well as with substitution of F by Cl or by Br. The lifetimes corresponding to spin–orbit relaxation are very long 852+621−282 ms for HBr+ and 965+546−323 ms for DBr+. They can be considered as equal within the quite large experimental uncertainty on the contribution of collisional deactivation.

Materialart: Digitale Medien

URL: http://dx.doi.org/10.1063/1.468179

Permalink

	Standort	Signatur	Erwartet	Verfügbarkeit

Andere fanden auch interessant ...

Artikel (Nationallizenzen)

Volltext

12

Digitale Medien

Photoionization electronic spectroscopy of AlAg (1994)

Robbins, D. L. ; Yeh, C. S. ; Pilgrim, J. S. ; [weitere]

College Park, Md. : American Institute of Physics (AIP)

The Journal of Chemical Physics 100 (1994), S. 4775-4783

zur Merkliste hinzufügen auf der Merkliste

Details

ISSN: 1089-7690

Quelle: AIP Digital Archive

Thema: Physik , Chemie und Pharmazie

Notizen: AlAg is produced in a supersonic molecular beam by laser vaporization of alloy samples in a pulsed nozzle cluster source. Electronic spectroscopy is studied with resonant two-photon photoionization. In addition to the two electronic excited states previously reported by Clements and Barrow, we have observed ten new states. Vibrational analyses are presented for each of these states, and rotational analyses are given for selected states. The number and characteristics of these excited states are compared to the predictions of recent ab initio calculations.

Materialart: Digitale Medien

URL: http://dx.doi.org/10.1063/1.466268

Permalink

	Standort	Signatur	Erwartet	Verfügbarkeit

Andere fanden auch interessant ...

Artikel (Nationallizenzen)

Volltext

13

Digitale Medien

The origin of β relaxation in organic glasses (1994)

Murthy, S. S. N. ; Sobhanadri, J. ; Gangasharan

College Park, Md. : American Institute of Physics (AIP)

The Journal of Chemical Physics 100 (1994), S. 4601-4606

zur Merkliste hinzufügen auf der Merkliste

Details

ISSN: 1089-7690

Quelle: AIP Digital Archive

Thema: Physik , Chemie und Pharmazie

Notizen: Using dielectric spectroscopy, some organic liquids consisting of mainly alkylhalides and acetic acid esters, have been studied over a wide frequency (106 to 10−3 Hz) and temperatures (down to 77 K). Measurements have also been made in the true liquid state at four microwave frequencies of 33, 22.4, 10, and 5.4 GHz in the temperature range 303–363 K. The high-temperature data reveals a significant contribution from the intramolecular (end- or side-group) rotation. The data corresponding to the supercooled state reveals a secondary (β) process in addition to the primary (α) process. The magnitude of the β process is found to be relatively large in systems which have greater contribution from the intramolecular process to the overall polarization at room temperature. The activation energies together with the side/end-group dependence of the magnitude of the β process suggest that the intramolecular process, though very much hindered during the process of supercooling, may survive to some extent in the glassy state to be realized as the β process. Our study suggests that the origin of the β process in these glasses may not be intermolecular in nature.

Materialart: Digitale Medien

URL: http://dx.doi.org/10.1063/1.466292

Permalink

	Standort	Signatur	Erwartet	Verfügbarkeit

Andere fanden auch interessant ...

Artikel (Nationallizenzen)

Volltext

14

Digitale Medien

Two-photon time-of-flight spectra of Xe2 (1994)

Dimov, S. S. ; Cai, J. Y. ; Lipson, R. H.

College Park, Md. : American Institute of Physics (AIP)

The Journal of Chemical Physics 101 (1994), S. 10313-10322

zur Merkliste hinzufügen auf der Merkliste

Details

ISSN: 1089-7690

Quelle: AIP Digital Archive

Thema: Physik , Chemie und Pharmazie

Notizen: Resonantly enhanced multiphoton ionization (REMPI) spectra of jet-cooled Xe2 are presented, covering the spectral region between ≈74 627 and 80 849 cm−1. Dimer ions produced by (2+1) REMPI excitation were mass selected in a linear time-of-flight (TOF) mass spectrometer. The vibrational and isotopic structure of several band systems dissociating to Xe* 5p56p and 5p55d asymptotes have been analyzed, many unambiguously for the first time, and molecular constants derived. Equilibrium bond lengths were estimated from Franck–Condon calculations. Insight into excited state predissociation was also obtained by recording atomic TOF excitation spectra. © 1994 American Institute of Physics.

Materialart: Digitale Medien

URL: http://dx.doi.org/10.1063/1.467911

Permalink

	Standort	Signatur	Erwartet	Verfügbarkeit

Andere fanden auch interessant ...

Artikel (Nationallizenzen)

Volltext

15

Digitale Medien

Ab initio study of nonadditive interactions in the Ar2HF and Ar2HCl clusters. II. Analysis of exchange and induction effects (1994)

Cybulski, S. M. ; Szcze(ogonek)s´niak, M. M. ; Cha (Slashthrough accent mark)asinski, G.

College Park, Md. : American Institute of Physics (AIP)

The Journal of Chemical Physics 101 (1994), S. 10708-10716

zur Merkliste hinzufügen auf der Merkliste

Details

ISSN: 1089-7690

Quelle: AIP Digital Archive

Thema: Physik , Chemie und Pharmazie

Notizen: The nonadditive effects are studied in Ar2HX (X=F, Cl) clusters using the supermolecular Møller–Plesset perturbation theory in conjunction with the perturbation theory of intermolecular forces. The range of geometrical variations include the rotation of HX within the plane of the cluster and perpendicular to it. The three-body effect is rigorously dissected into the three fundamental nonadditive components: exchange, induction, and dispersion. The exchange nonadditivity is further divided into two terms: ES3, the electrostatic interaction between the HX and Ar2 subunits due to the appearance of exchange-induced quadrupole moment on Ar2 [Cooper and Hutson, J. Chem. Phys. 98, 5337 (1993)], and its exchange counterpart X3. ES3 is physically interpreted as originating from the interatomic electron exchanges within the Ar2 part. The X3 term originates from triple exchanges among all three monomers. The induction nonadditivity is dominated by the third-order effect describing the interaction of moments induced on the Ar atoms by the field of HX. This effect is faithfully represented by the multipole approximation. © 1994 American Institute of Physics.

Materialart: Digitale Medien

URL: http://dx.doi.org/10.1063/1.468504

Permalink

	Standort	Signatur	Erwartet	Verfügbarkeit

Andere fanden auch interessant ...

Artikel (Nationallizenzen)

Volltext

16

Digitale Medien

The S0↔S1 transition of trans-β-methyl styrene (1994)

Drescher, W. ; Kendler, S. ; Zilberg, S. ; [weitere]

College Park, Md. : American Institute of Physics (AIP)

The Journal of Chemical Physics 101 (1994), S. 11082-11083

zur Merkliste hinzufügen auf der Merkliste

Details

ISSN: 1089-7690

Quelle: AIP Digital Archive

Thema: Physik , Chemie und Pharmazie

Notizen: The vibronic structure of the fluorescence excitation and emission spectra of trans-β-methyl styrene have been measured and analyzed, using an ab initio calculation. Good agreement between the experimental and calculated data, which indicate that the molecule is planar in both the ground and the S1 states, is obtained. © 1994 American Institute of Physics.

Materialart: Digitale Medien

URL: http://dx.doi.org/10.1063/1.467796

Permalink

	Standort	Signatur	Erwartet	Verfügbarkeit

Andere fanden auch interessant ...

Artikel (Nationallizenzen)

Volltext

17

Digitale Medien

Textures and phase transitions in Langmuir monolayers of fatty acids. A comparative Brewster angle microscope and polarized fluorescence microscope study (1994)

Rivière, S. ; Hénon, S. ; Meunier, J. ; [weitere]

College Park, Md. : American Institute of Physics (AIP)

The Journal of Chemical Physics 101 (1994), S. 10045-10051

zur Merkliste hinzufügen auf der Merkliste

Details

ISSN: 1089-7690

Quelle: AIP Digital Archive

Thema: Physik , Chemie und Pharmazie

Notizen: Brewster angle microscopy (BAM) and polarized fluorescence microscopy (PFM) are used to observe the distinctive textures of and the transitions between condensed phases in Langmuir monolayers of n-alkanoic acids. BAM is sensitive to film anisotropy even when the molecules are not tilted as long as the unit cell is anisotropic. Every transition is visible with one or both of the techniques, either as a dramatic change in the degree of contrast or as a sudden alteration of the mosaic domain texture. The two techniques are generally consistent, although the presence of the fluorescent probe impurity (for PFM) causes a subtle difference in the appearance of one transition and small shifts in transition surface pressures. © 1994 American Institute of Physics.

Materialart: Digitale Medien

URL: http://dx.doi.org/10.1063/1.467993

Permalink

	Standort	Signatur	Erwartet	Verfügbarkeit

Andere fanden auch interessant ...

Artikel (Nationallizenzen)

Volltext

18

Digitale Medien

Composition fluctuation induced depolarized Rayleigh scattering from diblock copolymer melts (1994)

Jian, T. ; Semenov, A. N. ; Anastasiadis, S. H. ; [weitere]

College Park, Md. : American Institute of Physics (AIP)

The Journal of Chemical Physics 100 (1994), S. 3286-3296

zur Merkliste hinzufügen auf der Merkliste

Details

ISSN: 1089-7690

Quelle: AIP Digital Archive

Thema: Physik , Chemie und Pharmazie

Notizen: Dynamic light scattering in the depolarized geometry has been used to investigate the pretransitional behavior of diblock copolymer melts near the order–disorder transition (ODT). Besides the segmental orientational dynamics, an additional slow relaxation process contributes to the dynamic depolarized intensity. This new relaxation mode exhibits an almost exponential shape, a wave vector (q) independent relaxation rate, and a strongly temperature dependent amplitude that compares with the temperature dependence of the maximum of the static structure factor at q*, measured with small-angle x-ray scattering. An account for the characteristics of this new relaxation process is based on the coupling between orientation and order parameter fluctuations. The depolarized intensity is due to orientation and/or extension of the copolymer chains in the pretransitional state above the ODT, with the relevant length scale of the slow orientation fluctuations being close to 2π/q*.

Materialart: Digitale Medien

URL: http://dx.doi.org/10.1063/1.466419

Permalink

	Standort	Signatur	Erwartet	Verfügbarkeit

Andere fanden auch interessant ...

Artikel (Nationallizenzen)

Volltext

19

Digitale Medien

Structure of confined alkane liquids (1994)

Walley, K. P. ; Schweizer, K. S. ; Peanasky, J. ; [weitere]

College Park, Md. : American Institute of Physics (AIP)

The Journal of Chemical Physics 100 (1994), S. 3361-3364

zur Merkliste hinzufügen auf der Merkliste

Details

ISSN: 1089-7690

Quelle: AIP Digital Archive

Thema: Physik , Chemie und Pharmazie

Notizen: Polymer integral equation theory is employed to calculate structural properties of undecane and short polymer liquids confined between parallel plates. A strong dependence is found on the strength of fluid–surface interactions which is consistent with solvation force measurements using both strongly attractive mica and weakly repulsive hydrocarbon surfaces.

Materialart: Digitale Medien

URL: http://dx.doi.org/10.1063/1.466377

Permalink

	Standort	Signatur	Erwartet	Verfügbarkeit

Andere fanden auch interessant ...

Artikel (Nationallizenzen)

Volltext

20

Digitale Medien

A discharge flow-photoionization mass spectrometric study of HOBr(X 1A'): Photoion yield spectrum, ionization energy, and thermochemistry (1994)

Monks, P. S. ; Stief, L. J. ; Krauss, M. ; [weitere]

College Park, Md. : American Institute of Physics (AIP)

The Journal of Chemical Physics 100 (1994), S. 1902-1907

zur Merkliste hinzufügen auf der Merkliste

Details

ISSN: 1089-7690

Quelle: AIP Digital Archive

Thema: Physik , Chemie und Pharmazie

Notizen: The photoion yield spectrum of HOBr was measured over the wavelength range λ=108–121 nm by using a discharge flow-photoionization mass spectrometer apparatus coupled to a synchrotron radiation source. HOBr was generated by the reaction of OH with molecular bromine. A value of (10.62±0.04) eV was obtained for the adiabatic ionization energy (I.E.) of HOBr from photoion thresholds, corresponding to the HOBr+(2A‘)←HOBr(1A') transition. The structure observed in the spectrum is discussed in terms of the available states for HOBr+, which have been determined using multiconfiguration-self-consistent field calculations. A new value for ΔH0f 298(HOBr) of −9 kcal mol−1 is derived from I.E.(HOBr) and estimates of ΔHf(HOBr+).

Materialart: Digitale Medien

URL: http://dx.doi.org/10.1063/1.466543

Permalink

	Standort	Signatur	Erwartet	Verfügbarkeit

Andere fanden auch interessant ...

Artikel (Nationallizenzen)

Volltext