Effect of thermal vibration and the solid-liquid phase transition on electron dynamics: An inelastic x-ray-scattering study on Al

Inelastic-x-ray-scattering measurements of the dynamic structure factor, $S(q,\omega ),$ of electrons in Al both in the solid phase at rising temperatures and in the liquid are presented. The double-peak structure of $S(q,\omega )$ for $q>\mathrm{}{q}_c$ ($q_c=$plasmon cutoff vector), diminishes gradually with decreasing strength of the ion-core potential; the peak position and the sloping plateau of the $S(q,\omega )$ spectra for $q>\mathrm{}{q}_c$ do not exhibit marked changes upon melting. The plasmon energy for $q<\mathrm{}{q}_c$ shifts according to the variation of the electron density upon heating and melting, and does not respond to the loss of long-range order.