COLLISION-INDUCED HYPER-RAYLEIGH LIGHT-SCATTERING IN CCL4

Measurements of hyper-Rayleigh scattering in carbon tetrachloride liqu id and vapour indicate that interaction induced contributions account for more than half of the scattered intensity from the liquid phase. T he spectral characteristics of hyper-Rayleigh scattering from carbon t etrachloride are influenced by the effects of hindered rotation, orien tational correlations, and dipole-induced-dipole and octupole-induced- dipole interactions, as well as the usual local field factors. The uni molecular contribution is associated with the narrow Lorentzian featur e of the hyper-Rayleigh spectrum. The first hyperpolarizability beta d etermined from the intensity of just the narrow Lorentzian feature of the liquid hyper-Rayleigh spectrum agrees with the gas phase value of beta, but is 1.57 times smaller than the value obtained by including t he entire liquid hyper-Rayleigh spectrum.