Low frequency depolarized light scattering in the VH geometry from quinoline

Abstract

Low frequency depolarized light scattering spectra in the VH geometry are measured in liquid and supercooled quinoline from 37 to −35 °C and compared with the theory of Gershon and Oppenheim. The spectra are separated into contributions of different modes which can be dissipative and/or vibrating according to Gershon and Oppenheim’s results, and it is shown that a central dip does not necessarily mean dissipative modes, e.g., at 2 °C. Shear viscosities deduced from the spectra are close to values measured macroscopically. Orientational relaxation times obtained are exponential vs 1/T over the temperature range measured, and the coupling parameter between the orientational and the linear momentum densities is about proportional to the viscosity width.