摘要:

AbstractThe polarized hyper‐Raman spectra and the polaritons were studied in liquid PCl3and C2Cl4. The TO‐LO splitting of the dipole modes was found in PCl3[480 (TO)‐515 (LO) cm−1and 494 (LO)‐500 (TO) cm−1]. The LO and TO mechanical modes vanished in the back‐scattering and forward‐scattering hyper‐Raman spectra, respectively. The possibility of observation of the splitting due to polariton‐vibration resonance is analysed. It is shown that the observation at ω≲300 cm−1is possible if the oscillator strength of the vibration exceeds 0.1. Using the value of the splitting, the oscillator strengths were estimated for a number of dipole modes in PCl3and C2Cl4. The trend of the polariton branches and the observation of the resonances showed that all dipole modes of a liquid have the same symmetry, although the symmetry of these modes was different when considered in terms of the 'molecular' selection rules. To analyse the selection rules of the vibrational spectra of liquids it is necessary to invoke

ISSN:0377-0486    

DOI:10.1002/jrs.1250160202

出版商:John Wiley&Sons, Ltd.    

年代:1985

数据来源: WILEY

摘要:

AbstractRaman spectra of some bands in the plastic phase of hexamethylethane have been recorded as a function of temperature. Interesting features related to the molecular reorientations and librations have been derived from the band shape analysis of F2gand Eglow‐frequency spectra. A novel temperature dependence of the libration width has been observed. The analysis of the internal modes' bandwidths at ν1= 878 cm−1and ν2= 475 cm−1provides consistent results for the monomolecular reorientational d

ISSN:0377-0486    

DOI:10.1002/jrs.1250160203

出版商:John Wiley&Sons, Ltd.    

年代:1985

数据来源: WILEY

摘要:

AbstractRaman and infrared spectra of tetramethylcyclobutane‐1, 3‐dithione (TMCBDT) and the fully deuteriated derivative (TMCBDT‐d12) have been recorded. A reasonably complete set of vibrational frequencies and assignments are presented for the two molecules. The symmetric CS stretching mode was observed at 1328 cm−1for TMCBDT and at 1352 cm−1for TMCBDT‐d12. The antisymmetric CS stretching mode occurs at lower frequencies of 1167 cm−1for TMCBDT and 1158 cm−1for the deuteriated molecule. This is consistent with previous observations for tetramethylcyclobutanedione. Ground‐state vibrational frequencies of several modes involved in progressions in the n→ π*electronic absorption s

ISSN:0377-0486    

DOI:10.1002/jrs.1250160204

出版商:John Wiley&Sons, Ltd.    

年代:1985

数据来源: WILEY

摘要:

AbstractNew Raman and IR spectra have been recorded for adenine and its analogues substituted with deuterium on the nitrogen atoms, on the carbon at position 8 and on both. The bands observed have been assigned on the basis of experimental data and a normal coordinate analysis. The latter was carried out by means of a Urey‐Bradley force field comparable to that already established for guanine. Assignments are discussed in the light of observed and calculated frequencies and isotopic shift

ISSN:0377-0486    

DOI:10.1002/jrs.1250160205

出版商:John Wiley&Sons, Ltd.    

年代:1985

数据来源: WILEY

摘要:

AbstractThe depolarization ratio‐dispersion curves and the excitation profiles of oxyhaemoglobin (1375, 1583, 1638 cm−1) and ferrocytochromecRaman lines have been measured in the pre‐resonant and resonant regions of theQ‐band, respectively. The experimental data are interpreted by fifth‐order Loudon theory of the polarizibility tensor, including symmetry lowering of the haem group and the creation and subsequent annihilation of a second phonon. The fitting constants needed to fit the experimental data are related to vibronic coupling matrix elements due to the Raman and the second phonon. They also contain distortions δQΓ, lowering the ideal D4h, symmetry of the functional haem group. These distortions can be classified due to the Raman‐allowed representationsA1g,B1g,B2gandA2ginD4hsymmetry. Thus, from the fitting procedure one obtains detailed information about the actual symmetry of t

ISSN:0377-0486    

DOI:10.1002/jrs.1250160206

出版商:John Wiley&Sons, Ltd.    

年代:1985

数据来源: WILEY

摘要:

AbstractThe Raman spectrum of the Coriolis interacting ν2, ν5bands of CD3Cl was recorded with a resolution ofca0.6 cm−1. Using the vibrational‐rotational parameters of Yamada and Hirota, a computer simulation of the Raman contour was performed, yielding relative values of Raman polarizability derivatives for these bands. By comparison with the absolute intensity measurement of Orzaet al., absolute values of the Raman polarizabilities were obtained. The sign of the Raman intensity perturbation was found to be neg

ISSN:0377-0486    

DOI:10.1002/jrs.1250160207

出版商:John Wiley&Sons, Ltd.    

年代:1985

数据来源: WILEY

摘要:

AbstractThe electronic (800‐400 nm), infrared, ordinary Raman (400‐20 cm−1) and resonance Raman spectra (3000‐20 cm−1) of several hexahalodi(aquo)dimolybdate(II)anions, Mo2X6(H2O)22−, with X = Cl, Br, I, containing quadruple metalmetal bonds were investigated. The electronic spectra of the solid compounds at various temperatures (25, 100 and 300 K) show intense and sometimes structured bands in the visible region (510‐580 nm) assigned to the expected δ → δ*transitions; energy values of the 0 → 0 transition, of the excited‐state metal‐metal stretching vibrational frequency and of the damping factors were thus determined. From the infrared and Raman spectra, the skeletal stretching modes in these binuclear anions have been localized, and from resonance Raman results the ground‐state harmonic frequencies, anharmonic constants, force constants and dissociation energies of the Mo‐Mo bonds have been estimated.Finally, within the Franck‐Condon model for resonance Raman scattering, theoretical and experimental excitation profiles of the metal‐metal fundamental and its first overtone have been compared in order to obtain accurate values of the displacement parameters (Ble≈︁ 2.78‐2.53) and of the shift in equilibrium positions (Δr1= 0.13‐0.12 Å); these magnitudes are consistent with other observations and these data represent one of the fir

ISSN:0377-0486    

DOI:10.1002/jrs.1250160208

出版商:John Wiley&Sons, Ltd.    

年代:1985

数据来源: WILEY

摘要:

AbstractThe low‐frequency Raman spectra of gaseous formic and acetic acids are corrected from counts per second to the square of the polarizability derivative with respect to the normal coordinate. The acetic acid peak at 98.9 cm−1is shifted to 106 cm−1by this correction, necessitating minor reassignments. The intense, broad, 'Rayleigh Line' is greatly reduced by this correction, to reveal scattering by pure rotational m

ISSN:0377-0486    

DOI:10.1002/jrs.1250160209

出版商:John Wiley&Sons, Ltd.    

年代:1985

数据来源: WILEY

ISSN:0377-0486    

DOI:10.1002/jrs.1250160201

出版商:John Wiley&Sons, Ltd.    

年代:1985

数据来源: WILEY