Raman and depolarized Rayleigh scattering studies of molecular motions of liquid 1,2,5-thiadiazole

Abstract

The polarized and depolarized Raman components of the ν₃, ν₄, ν₅, and ν₆ totally symmetric vibrations of pure liquid 1,2,5‐thiadiazole were measured as a function of temperature. The half‐widths of the polarized spectra for the ν₃, ν₄, and ν₅ modes significantly decreased as temperature was increased. The complications affecting the separation of rotational motion from the depolarized anisotropic spectra of asymmetric top molecules were analyzed. Raman correlation times, which correspond to the weighted contribution from rotation about various axes, were obtained. Depolarized Rayleigh reorientational relaxation times for pure 1,2,5‐thiadiazole were also measured. The depolarized Rayleigh results agreed with only the ν₆ Raman results. The temperature dependence of the Raman depolarization ratios was also investigated.