Reorientation of methylbenzene molecules in the liquid phase: A comparative Raman band shape analysis

Abstract

A comparative Raman band shape study of the reorientation of monosubstituted benzene molecules (C6H5X, X = CH,, CH,Cl, CHCl,, CCl, and C=CCH,) in the liquid phase has been performed. Reorientational correlation functions appear to be less sensitive to molecular reorientation about the major axis ( Z axis) than to rotation of the axis itself, approaching a symmetric top case. Molecular motion anisotropy is found to increase in the order C6H5CH3 < C6H5CH2Cl < C,H5CHCl2 < C6H5CC13 < C6H&CCH3 as the rotation about the Z axis becomes increasingly preferred. These results are in agreement with NMR spin-lattice relaxation data.As expected for liquids with important intermolecular interactions, both the free rotor and Kubo's model fail to fit the experimental correlation functions.