Path integral Monte Carlo studies of the behavior of excess electrons in simple fluids

Abstract

The behavior of an excess electron in helium (at T=309 K) and xenon (at T=309 K and T=248 K) is studied over a range of fluid densities (ρ*=ρσ3=0.1–0.9). A path integral Monte Carlo technique is used to model the ‘‘quantum’’ electron which interacts through pseudopotentials with the ‘‘classical’’ solvent particles. In helium, the electron becomes confined in a cavity in the solvent and behaves like a particle in a spherical box. We observe contrasting behavior in the more polarizable xenon solvent where the electron exists in a ‘‘quasifree’’ state. A variety of equilibrium properties of the electron and the solvent are presented to characterize the structure of the different systems. The anomolous density dependence of the experimental electron mobility along the coexistence curve in xenon can be understood qualitatively in terms of the equilibrium structures we observe at the different solvent densities.