GROUND-STATE INTERMOLECULAR SPECTROSCOPY AND PENDULAR STATES IN BENZENE-ARGON

The results of nonlinear Raman spectroscopy at 0.03 cm(-1) resolution on the intermolecular transitions of the perprotonated and perdeuterat ed isotopomers of benzene-Ar are reported. Five bands were observed fo r each species. For each, band-contour measurements were performed. Th ese, when compared to simulated contours, allow for the unambiguous as signment of the bands in terms of the two intermolecular fundamentals, the two components of the first bending overtone, and the bend-stretc h combination band. Further, it is shown that the measured contours ar e ''pendular'' contours arising from species in optical-held-induced p endular states. The results are discussed in terms of (a) prior experi ments on and calculations of the intermolecular level structure of ben zene-Ar, (b) the mechanisms giving rise to the Raman intensities of in termolecular transitions, and (c) their implications regarding the pre valence of pendular behavior in nonlinear Raman experiments on jet-coo led species. (C) 1997 American Institute of Physics.