The collective diffusion coefficient was studied for a system of particles adsorbed on a surface with 2 non-equivalent adsorption sites. The non-equilibrium conditions were characterized by a non-equilibrium distribution of atoms between adsorption sites with differing adsorption energies. The analysis showed that non-equilibrium conditions strongly influenced the step-like dependence of diffusion coefficients on coverage, as determined under equilibrium conditions for non-interactive adparticles, and that the diffusion coefficient could even exhibit the opposite behavior. The appearance of a local maximum was observed far from equilibrium.

Dynamics of Ad-Particles under Far from Equilibrium Conditions. Z.Chvoj: Surface Science, 2002, 507-510, 114-8