Testing of mode-coupling theory through impulsive stimulated thermal scattering

Impulsive stimulated thermal scattering, a time-domain light scattering technique spanning ps-ms time scales, allows a number of experimental tests of mode-coupling theory (MCT) predictions. Time-dependent acoustic responses and also slower relaxational responses to sudden heating are observed. From the acoustic responses, mechanical modulus spectra are deduced which permit testing of MCT predictions for α and β relaxation dynamics. From the relative intensities of acoustic and relaxational signals, the prediction of a cusp in the temperature-dependence of the nonergodicity parameter (Debye-Waller factor) can be tested. ISTS results from a concentrated (13 m%) aqueous LiCl solution, the molten salt [Ca(NO3)2]0.4[KNO3]0.6, and salol are reviewed.