Electron dynamics at a positive ion.

The dynamics of electrons in the presence of a positive ion is considered for conditions of weak electron-electron coupling but strong electron-ion coupling. The equilibrium electron density and the electric field time correlation functions are evaluated for semiclassical conditions using a classical statistical mechanics with a regularized electron-ion interaction for molecular dynamics simulation (MD). Results are reported for the autocorrelation function of the electron electric field at the ion for 0< or =Z< or =40 , including conditions of strong electron-ion coupling. The electron stopping power and self-diffusion coefficient are determined from these results. Interpretation is provided by a theoretical analysis using the nonlinear Vlasov equation for the equilibrium structure, and a corresponding linear Vlasov equation for time correlation functions. The agreement of a simple mean field model with the semiclassical MD simulation is found to be quite good except for one state condition.