An efficient numerical method for the calculation of the collective diffusion coefficient was developed. The method was based upon the Bortz–Kalos–Lebowitz algorithm, with local up-dating of the particle lists for each process, coupled to the memory expansion for the calculation of the center-of-mass diffusion coefficient. The method was applied to diffusion in a 2-dimensional lattice gas model, of square symmetry, with repulsive lateral interactions. The numerical results were compared with Darken equation and dynamic mean-field theory approximations.

An Efficient Method for Computing Collective Diffusion in a Strongly Interacting Lattice Gas. A.Serra, R.Ferrando: Surface Science, 2002, 515[2-3], 588-96