TIME-RESOLVED COHERENT STOKES RAMAN-SPECTROSCOPY (CSRS) OF BENZENE

Femtosecond time-resolved coherent Stokes Raman spectroscopy (CSRS) signals of benzene-h6, benzene-d6, and their 1:1 binary mixture are investigated at room temperature with two different polarization geometries. The reorientational correlation time of benzene as well as the vibrational dephasing time of the nu-1 ring-breathing mode have been measured precisely. Bohr frequency difference beats have been resolved between the nu-1 modes of C-12-6H6 and C-12-5 C-13H6 protonated benzenes and the C-12-6D6 and C-12-5 C-13D6 deuterated benzenes that are present at natural abundances in their neat liquids. There is no evidence for stochastic line broadening phenomena other than in their fast modulation limit even on the 100 fs time scale of these experiments.