Temporally Two-Dimensional Fifth-Order Raman Scattering on Intermolecular Vibrations in Cs2/Pentane Binary Mixtures

Third- and fifth-order impulsive stimulated Raman scattering experiments are performed to study low-frequency intermolecular vibrations in CS2/pentane binary mixtures. The changes of the optical Kerr effect response cannot be assigned unequivocally to a single microscopic process. In particular, the homogeneous and inhomogeneous line broadening mechanisms cannot be determined. Temporally two-dimensional Raman scattering experiments indicate that the correlation time of fluctuations of the intermolecular potential decreases upon dilution. The experimental results give evidence of strong coupling between the ultrafast coherent vibrations and the slow reorientational diffusion.