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Hyper‐Raman spectra and polariton‐vibration resonances in liquid C 2 Cl 4 and PCl 3
Author(s) -
Denisov V. N.,
Mavrin B. N.,
Podobedov V. B.,
Sterin Kh. E.
Publication year - 1985
Publication title -
journal of raman spectroscopy
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.748
H-Index - 110
eISSN - 1097-4555
pISSN - 0377-0486
DOI - 10.1002/jrs.1250160202
Subject(s) - raman spectroscopy , polariton , resonance (particle physics) , dipole , spectral line , raman scattering , oscillator strength , molecular physics , molecular vibration , symmetry (geometry) , chemistry , normal mode , vibration , atomic physics , analytical chemistry (journal) , physics , condensed matter physics , optics , geometry , quantum mechanics , mathematics , organic chemistry , chromatography
The polarized hyper‐Raman spectra and the polaritons were studied in liquid PCl 3 and C 2 Cl 4 . The TO‐LO splitting of the dipole modes was found in PCl 3 [480 (TO)‐515 (LO) cm −1 and 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 −1 is 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 PCl 3 and C 2 Cl 4 . 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 its macroscopic symmetry.