Effective medium theory of collective diffusion of lattice gases in lattices with site energy disorder

Abstract

Collective diffusion of lattice gases of arbitrary concentrations is investigated in lattices of dimensions d>or=2 with randomly distributed site energies. The Gaussian, exponential and dichotomic distributions of site energies are employed. An effective medium theory of the coefficient of collective diffusion is given using symmetrized single-particle transition rates. A previous phenomenological theory is rederived in the limit d to infinity . The effective medium theory gives good agreement with simulation data at smaller particle concentrations, and rough agreement at large particle concentrations.