Phonon Dispersion Curves in High-Temperature Solids from Liquid Structure Factors

The density functional method is used to relate the phonon dispersion curves in a crystal near melting to the structure factor of its liquid near freezing. An illustration is given for potassium, by evaluation of the dispersion curves for all polarizations along several symmetry directions in the Brillouin zone from measured liquid structure factors and comparison with neutron inelastic scattering data. The elastic limit in a monatomic crystal and the plasma frequency limit in the classical Wigner crystal are also briefly discussed.