Depolarized Rayleigh Scattering: Reorientational Motion and Orientational Correlations in Acetonitrile and Carbon Disulfide

Depolarized Rayleigh scattering experiments on neat acetonitrile and carbon disulfide as well as on mixtures of these liquids with carbon tetrachloride are reported. The collective reorientational correlation time τ LS has been determined which is then compared with the single particle correlation time τ S . From the comparison information on an orientational structure factor g (2) , which is closely related to the Kirkwood g ‐factor of polar fluids, can be obtained. Combination of g (2) and Kirkwood g ‐factor results shows that a preferred antiparallel alignment is the most probable orientational structure in acetonitrile. For CS 2 a Kirkwood g ‐factor cannot be defined due to symmetry. Here the experiments indicate a preferred parallel arrangement of neighbouring molecules.