Polarization selectivity in fifth-order electronically nonresonant Raman scattering from CS2

This paper presents several experimentally collected tensor elements of the direct fifth-order Raman signal of room temperature CS2. All results were collected so as to reduce contamination from third-order cascade signals, a nd it is shown that while these cascade signals are of varying importance i n different tensor elements, phase matching considerations are sufficient t o make the direct fifth-order signal the dominant signal in every tensor el ement collected. We show, as predicted, that the different tensor elements appear to weight particular Liouville pathways of the direct fifth-order si gnal, and thus particular dynamics of the studied system, differently. The magic angle signals are shown to contain information about the intermolecul ar vibrational echo and to put a limit on the time scale of rephasing of th e room temperature liquid. The R-yzzzzy tensor element, in conjunction with the R-yyzzzz tensor element, is shown to be useful in studying the pure de phasing and population dynamics of the liquid. From these data it appears t hat population dynamics occur on a much longer time scale than pure dephasi ng dynamics, even though this is not obvious for the intermolecular motions of a room temperature liquid that are studied here. Further, intensities a nd behaviors of different tensor elements of the experimental data are comp ared with the only detailed theory currently available that explicitly incl udes polarization dependence. (C) 2001 American Institute of Physics.