PROBING INTERMOLECULAR DYNAMICS IN LIQUIDS BY FEMTOSECOND OPTICAL KERR-EFFECT SPECTROSCOPY - EFFECTS OF MOLECULAR SYMMETRY

Intermolecular dynamics in a series of nitriles and substituted methanes are investigated using optical-heterodyne-detected Raman-induced Kerr effect spectroscopy (OHD-RIKES) with similar to 30 fs laser pulses. The results obtained unequivocally establish a correlation between molecular symmetry and the ratio of intermolecular vs intramolecular contribution to the Kerr signal. Quantitative connections between molecular anisotropy and optical Kerr measurements are discussed. The utility of low-frequency spectral densities measured by OHD-RIKES in relation to studies on dynamics in liquids is addressed.