Diffusion coefficients in a nonideal lattice gas with high concentration gradients

Expressions for the flow of migrating particles and for the diffusion coefficient in a nonideal lattice gas are derived from the equations of chemical kinetics. The diffusion coefficients depend not only on the concentration of the chemical components the gas, but also on their gradients and surface reactions. The diffusion coefficients are linear operators: the direction of flow may deviate from the gradient even for a one-component gas. These factors are shown to be essential at high gradients. © 2000 Kluwer Academic/Plenum Publishers.