What do we know about the microscopic motion in simple liquid metals and what can we learn from inelastic scattering experiments?

Abstract

A short survey on recent inelastic scattering work on liquid alkali metals is given. The classification of liquid alkalis as “simple liquids” is questioned from analysing experimental data measured within the full liquid range from melting point conditions up to the immediate vicinity of the liquid vapour critical point. Depending on density, the particle dynamics passes through several characteristic domains. At sufficiently high density where the electron gas determines the interparticle interactions, the motional behaviour is rather solid-like and essentially two relaxation mechanisms are needed to correctly account for the single particle as well as for the collective dynamics. At sufficiently reduced density, electron localisation must be taken into account favouring the formation of molecular species. Their internal degrees of freedom resulting from this chemical variation gradually determine the shape of the scattering law.