Light scattering from shear modes in liquid salol

Abstract

Depolarized spectra of liquid salol have been observed and analyzed over a range of temperature, from 122 to −22 °C, with the viscosity varying from ∼2 to more than 10⁴ cP. At the lowest temperatures, the spectra exhibit a central line and well‐separated Brillouin components, characteristic of light scattering by oscillatory shear waves. As the temperature is raised, the Brillouin components merge with the central line. At the highest temperatures, broad depolarized doublets with intensity minima at the exciting frequency appear, and are ascribed to light scattering from highly damped shear modes. The spectra observed over the entire temperature range are shown to be in good agreement with the ’’two variable’’ theory of Andersen and Pecora.