Dynamic structure factor for the electron gas in metallic systems

Abstract

A microscopic calculation is presented for the dynamic structure factor of the electron gas at metallic densities. The calculation is based on a theory of dynamic correlations in the electron gas, which is valid for high to metallic electron densities and which strictly maintains the conservation laws. A detailed comparison is made to the multiple peaks experimentally observed in the dynamic structure factors of Li and Be at momentum transfers greater than the Fermi momentum. From the quantitative agreement obtained, we conclude that the peak structures are a direct result of short-range Coulomb scattering correlations between two excited electrons. These correlations are frequency sensitive and highly nonlocal, and cannot be replicated by mean-field approximations.