Generic Structural Relaxation in Supercooled Liquids

One of the unsolved problems of dynamics in supercooled liquids are the differences in spectral shape of the structural relaxation observed among different methods and substances, and a possible generic line shape has long been debated. We show that the light scattering spectra of very different systems, e.g., hydrogen bonding, van der Waals liquids, and ionic systems, almost perfectly superimpose and show a generic line shape of the structural relaxation, following proportional to omega(-1/2) at high frequencies. In dielectric spectra the generic behavior is recovered only for systems with low dipole moment, while in strongly dipolar liquids additional cross-correlation contributions mask the generic structural relaxation.

Automated summary

Research has shown that the light scattering spectra of different systems almost perfectly overlap, exhibiting a generic line shape of structural relaxation, particularly proportional to omega(-1/2) at high frequencies. In dielectric spectra, the generic behavior is only recovered for systems with low dipole moment.