Polarized and depolarized Brillouin scattering from 0.4 Ca(NO3)2-0.6KNO3 was investigated in the temperature range of 320 to 640 K using a six-pass Sandercock tandem Fabry-Perot interferometer. The polarized spectra were analyzed with a simplified version of mode-coupling theory, in which the small-q density fluctuation modes probed by light scattering couple only to pairs of modes at q0 corresponding to the first peak in the structure factor S(q). The density correlation function (q0,t) determined by neutron spin-echo experiments by Mezei et al. was used as input in the analysis, producing excellent fits to the experimental data. The depolarized spectra were analyzed with a phenomenological viscoelastic model including NO3- orientational relaxation.
ASJC Scopus subject areas
- Condensed Matter Physics