Behavior of excess electrons in classical fluids

Abstract

The theory of Chandler, Singh, and Richardson [J. Chem. Phys. 81, 1975 (1984)] is extended to calculate the effective mass of an excess electron in a liquid. For this, we introduce a fictitious driving force acting on the electron in the Hamiltonian and derive the effective mass from the acceleration rate against the force. The behavior of the electron is found to be very sensitive to the range d of the electron-fluid atom repulsive interaction. When the value of d/σ, where σ is the diameter of fluid atoms, is small (≊0.15), the electron is found to be in delocalized states having a very weak tendency toward localization at liquid densities. At large values of d/σ (≥0.5), on the other hand, the electron becomes localized for all temperatures as the solvent density is increased. Although the onset of the transition occurs at lower densities for larger values of d/σ, the width of the solvent density covered by the transition increases with temperature and the interaction range. For the intermediate values of d/σ (≊0.3) we find a sharp transition from delocalized to localized states as the temperature is lowered and the solvent density is increased. The transition temperature is found to be a nonmonotonic function of the solvent density.