Effect of pressure on the Raman depolarization ratio and the vibrational relaxation of thev1mode of liquid carbon tetrachloride at 22°C and 0–1·1 kbar

Abstract

The depolarization ratio of the v 1 Raman bands and the vibrational relaxation time of liquid carbon tetrachloride at 1 bar to 1·1 kbar were obtained by resolving the overlapping v 1 fundamental bands of five isotopic species and three broad combination bands by least-squares fitting. The eight component bands were represented by Voigt functions, the Gaussian widths of which were determined from the spectral slit widths. The resulting depolarization ratio of the v 1 fundamental bands at 1 bar is 0·0040, which is about 40% smaller than the depolarization ratio obtained from the whole region of the v 1 band. It decreases to 0·0033 at 1·15 kbar, which follows approximately the theoretical curve of the fluctuating-local-field model. The vibrational relaxation time obtained from the band width of the v 1 fundamental band of C35Cl4 decreases linearly from 6·0 ps at 1 bar to 4·7 ps at 1·15 kbar. The change is well reproduced by Schweizer and Chandler's kinetic model.