DEPOLARIZED RAYLEIGH-SCATTERING FROM SIMPLE MOLECULAR LIQUIDS - INVESTIGATION OF TRANSITIONS IN THE MELT

Depolarized Rayleigh scattering photometry has been employed to study the temperature dependence of the optical anisotropy for benzene, hexa fluorobenzene, and carbon tetrachloride. The depolarized Rayleigh inte nsity from carbon tetrachloride is entirely due to scattering by pairs of density fluctuations and increases monotonically with temperature. The total depolarized Rayleigh ratio R(VH) for benzene and hexafluoro benzene decreases smoothly and monotonically with temperature, in cont radiction to a recent report [J. Chem. Phys. 95, 1223 (1991)]. The tem perature dependence of the total depolarized Rayleigh ratio can be ana lyzed in terms of an increasing contribution due to scattering by pair s of density fluctuations and a decreasing contribution due to orienta tional fluctuations of optically anisotropic molecules. No anomalous b ehavior is observed anywhere in the Liquid range for these three fluid s. (C) 1995 American Institute of Physics.