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  • 1990-1994  (5)
  • 1
    Electronic Resource
    Electronic Resource
    Inelastic incoherent neutron scattering study of molecular motions of n-nonadecane in urea chlatrate (1990)
    College Park, Md. : American Institute of Physics (AIP)
    The Journal of Chemical Physics 93 (1990), S. 3536-3541 
    Details
    ISSN: 1089-7690
    Source: AIP Digital Archive
    Topics: Physics , Chemistry and Pharmacology
    Notes: Inelastic incoherent neutron scattering experiments were performed on semi-oriented samples of C19H40 –urea chlatrates over the 1.5–306 K temperature range. Using appropriate sample orientations and different instrumental resolutions, all the motions parallel or perpendicular to the main chain axes were analyzed in the 0–400 cm−1 frequency range. In the quasielastic region and for the Q momentum transfer vector parallel to the chain axes, a side peak attributed to a longitudinal acoustic mode was evidenced at 12 cm−1 at 1.5 K (overdamped at higher temperatures) in addition to large quasielastic broadenings due to restricted translational motions. For Q perpendicular to the chains, a diffusive rotational process was also evidenced in the disordered solid phase. All these results are discussed and compared to literature data.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.458835
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    Paper (German National Licenses)
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  • 2
    Electronic Resource
    Electronic Resource
    Molecular motions of alkylenediammonium chains in the layer-type compounds (NH3-(CH2)n-NH3)MnCl4, n = 3,4,5: an incoherent neutron scattering study (1990)
    s.l. : American Chemical Society
    The @journal of physical chemistry 〈Washington, DC〉 94 (1990), S. 3438-3449 
    Details
    Source: ACS Legacy Archives
    Topics: Chemistry and Pharmacology , Physics
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1021/j100372a017
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    Paper (German National Licenses)
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  • 3
    Electronic Resource
    Electronic Resource
    A Raman study of the misfit layer compounds, (SnS)1.17NbS2 and (PbS)1.18 TiS2 (1992)
    Chichester [u.a.] : Wiley-Blackwell
    Journal of Raman Spectroscopy 23 (1992), S. 647-651 
    Details
    ISSN: 0377-0486
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: The Raman and resonance Raman spectra (850-20 cm-1) of powdered samples of the misfit layer compounds (SnS)1.17NbS2 and (PbS)1.18TiS2 at 300 K have been investigated. In partial agreement with structural data, vibrational assignments are proposed for most of the internal modes of the ‘MS’ and ‘TS2’ sublattices and the band wavenumbers are compared to those in the 2H-NbS2 and IT-TiS2 prototypes, in order to understand the interaction in which ‘MS’ acts as the donor part of the structure. Owing to their incommensurate modulated structures along the {ξ00} direction, characteristic Raman bands at 197 cm-1 (‘SnNbS3’) or 203 cm-1 (‘PbTiS3’), assigned to mostly TA or LA type modes, become Raman active due to a zone folding mechanism. New information about the lattice dynamics in the ‘TS2’ sublayers is thus obtained.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jrs.1250231114
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    Paper (German National Licenses)
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  • 4
    Electronic Resource
    Electronic Resource
    Electronic, vibrational and resonance Raman spectra of the layered semiconducting compound NbS3A preliminary version of this work was presented at a recent conference. (1990)
    Chichester [u.a.] : Wiley-Blackwell
    Journal of Raman Spectroscopy 21 (1990), S. 337-349 
    Details
    ISSN: 0377-0486
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: The electronic (900-250 nm), infrared and Raman (600-10 cm-1) spectra of polycrystalline samples of NbS3 were investigated. A complete vibrational assignment is proposed and the band wavenumbers are compared for NbS3 and the related ZrS3 and NbS2Cl2. All the assignments have been checked by a complete valence force field calculation including intrachain, interchain and interlayer contributions. The potential energy distributions and mean square vibrational amplitudes so calculated and the values of force constants are in agreement with the two-dimensional character of the lattice dynamics in NbS3.In addition, an extensive resonance Raman study has been performed using various exciting radiations in the visible (676.4-457.9 nm) and near-UV regions (363.8 and 351.1 nm). The experimental unresolved Raman excitation profiles in the contour of two low-energy electronic transitions (λmax≍ 600 and 560 nm) exhibit interesting interference and exact resonance effects depending on the nature of the vibration. Taking account of multi-state interference phenomena and inhomogeneous broadening effects, these profiles compare well with the computed ones on the assumption of weakly displaced oscillators. This allows conclusions to be drawn about the scattering mechanisms and the nature of the first electronic excited states.
    Additional Material: 10 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jrs.1250210604
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    Paper (German National Licenses)
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  • 5
    Electronic Resource
    Electronic Resource
    Optical and resonance Raman scattering study of two ‘bisazo’ pigments derived from substituted benzene-2′-azonaphthols (1994)
    Chichester [u.a.] : Wiley-Blackwell
    Journal of Raman Spectroscopy 25 (1994), S. 477-488 
    Details
    ISSN: 0377-0486
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: The UV-visible (300-800 nm), Raman and resonance Raman (900-1700 cm-1) spectra of two bisazo scarlet RN and brown 5R pigments have been investigated in the solid state at 300 K. A detailed analysis of the resonance Raman spectra and excitation profiles of various fundamentals in the 900-1700 cm-1 range is reported through the visible absorption spectrum region: the vibrational assignments confirm that both substituted benzene-2′-azonaphthol derivatives are stabilized in their hydroxyazo form; the excitation profiles (EPs) established for many modes in each dye indicate interferences between two overlapping electronic manifolds. Taking account of multistate interference phenomena and inhomogeneous broadening effects, the observed EPs compare well with the calculated ones under the assumption of weakly displaced harmonic oscillators; this interpretation is supported by the observation of weak overtone and combination bands in the 1700-3000 cm-1 range.Finally, conclusions are drawn about the scattering mechanisms and the nature or degree of mixing of the first electronic excited states, which appear to be quite sensitive to the substituent (Cl or NO2) on the benzene rings. Such information can be helpful for the design and synthesis of new azo dyes with desirable properties.
    Additional Material: 10 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jrs.1250250708
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    Paper (German National Licenses)
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