Alternative ion-ion pair-potential model applied to molecular dynamics simulations of hot and dense plasmas: Al and Fe as examples

A model to calculate the ion-ion pair potentials in hot and dense plasmas is developed based on temperature-dependent density functional theory. The electronic structures, including the energy level and space distributions, are calculated using an average-atom model. The calculated electron space number density is divided into two parts: one is a uniformly distributed electronic sea ρ(r_b) with a density equal to the total electronic density at the ion sphere boundary, which is redistributed when space overlap occurs between the interacting ions; the left part of the electronic density ρ_i^2nd(r) represents the dramatic space variations of the electrons due to the nuclear attraction and the shell structure of the bound states, which maintains unchanged during the interactions between the ions. The pair potential is obtained through space integrations for the energy density functions of electron density. We present molecular dynamics simulations for the ion motion on the basis of the calculated pair potentials in a wide regime of density and temperature. As an example, hot and dense Al and Fe plasmas are simulated to give the equation of state and ion-ion pair distribution function. The results are in agreement with those of other theoretical models.