Statistical mechanical description and Monte Carlo simulation of diffusion in two-component lattice systems

Two different approaches based on linear response theory are considered in this paper. One of them results in quite general and exact expressions for kinetic diffusion coefficients in terms of mean square particle displacements that do not explicitly use any information concerning lattice gas dynamics or interparticle interactions. Relations between kinetic and chemical diffusion coefficients are considered as well. The other approach invokes the lattice gas master equation. It leads to a representation of the kinetic diffusion coefficient as a sum of static and memory-dependent terms. For the former, a closed form expression is derived in the case of thermally activated particle jumps in the model of traps. On this basis, the thermodynamic and memory aspects of multicomponent diffusion are considered. Monte Carlo (MC) simulation and calculation results are discussed. It is shown that memory effects are more pronounced as compared to one-component systems.