Analysis of intermolecular coordinate contributions to third-order ultrafast spectroscopy of liquids in the harmonic oscillator limit

A study of an inhomogeneously broadened quantum-mechanical harmonic oscillator model of intermolecular nuclear coordinates is applied to the analysis of subpicosecond optical Kerr effect dynamics of neat CS2 and its binary solutions in alkane solvents is presented. The results show that for an inhomogeneously broadened distribution of oscillators, this model predicts the naturally the bimodal character of the subpicosecond OKE dynamics, a Gaussian-like ultrafast decay and a slower, quasi-exponential relaxation, that is universally observed in molecular liquids.