Femtosecond time-resolved coherent anti-Stokes Raman spectroscopy of liquid benzene: A Kubo relaxation function analysis

Abstract

Femtosecond time-resolved coherent anti-Stokes Raman scattering (TRCARS) for the nu1 ring-breathing mode of neat benzene-h6 and benzene-d6 are reported at room temperature (25-degrees-C) and at 6.5-degrees-C. Ultrafast time resolution permits close investigation of the dephasing dynamics at early times. Deviation from the conventional exponential decay is found. The data are analyzed using Kubo line shape theory.. The correlation time tau(c) and the rms magnitude DELTA of the Bohr frequency modulation are determined for the process responsible for the vibrational dephasing and for the linewidth. Spinning motion is suggested as the stochastic process responsible for the vibrational dephasing in those neat liquids.