ORIGIN OF DEPOLARIZED LIGHT-SCATTERING IN SUPERCOOLED LIQUIDS - ORIENTATIONAL FLUCTUATION VERSUS INDUCED SCATTERING MECHANISMS

Depolarized Light scattering spectra of Liquid salol that have been an alyzed in recent studies of the liquid-glass transition are reexamined in order to determine the relative importance of orientational fluctu ations and interaction-induced scattering. First, the spectra of CCl4, CHCl3, CH2Cl2, and CS2 for which all the relevant parameters are know n are compared to theoretical predictions in order to verify the exper imental procedure. The same procedure is then applied to the molecular glass former salol for which we find that orientational fluctuations dominate at all frequencies up to at least 4000 GHz. We suggest that t he previously reported agreement between depolarized Light scattering spectra and predictions of the mode coupling theory for salol and othe r molecular glass forming materials results from coupling between rota tional and translational motions of the molecules.