Raman study of vibrational relaxation in liquid benzene-<i>d</i>6 at high pressure

Abstract

The Raman line shapes of two totally symmetric bands, ν1 and ν2, and five degenerate bands, ν11, ν15, ν16, ν17, and ν18, have been measured in liquid benzene-d6 as a function of pressure from 50 bar to 4 kbar and over the temperature range 30–120 °C. Some results for liquid benzene are also given. An approximate procedure is used to estimate the vibrational relaxation width for the degenerate Raman bands. The experimental results on vibrational relaxation are interpreted in terms of the vibrational dephasing model. The finding that vibrational relaxation broadening contributes differently to the total width of individual bands represents the most important result of this study. For all bands measured the vibrational relaxation width increases with increasing pressure but the change with temperature seems to be specific for each individual band.