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, and it is shown that while these cascade signals are of varying importance in different tensor elements, phase matching considerations are sufficient to make the direct fifth-order signal the dominant signal in every tensor element collected. We show, as predicted, that the different tensor elements appear to weight particular Liouville pathways of the direct fifth-order signal, and thus particular dynamics of the studied system, differently. The magic angle signals are shown to contain information about the intermolecular vibrational echo and to put a limit on the time scale of rephasing of the 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 dephasing and population dynamics of the liquid. From these data it appears that population dynamics occur on a much longer time scale than pure dephasing dynamics, even though this is not obvious for the intermolecular motions of a room temperature liquid that are studied here. Further, intensities and behaviors of different tensor elements of the experimental data are compared with the only detailed theory currently available that explicitly includes polarization dependence. (C) 2001 American Institute of Physics.