Diffusion in concentrated lattice gases. VI. Tracer diffusion on two coupled linear chains

Abstract

Tagged-particle diffusion is investigated on a system of two coupled linear chains with an arbitrary ratio of the jump rates for jumps to unoccupied neighboring sites in the two principal directions. The mean-square displacement of a tagged particle is investigated both theoretically and by Monte Carlo simulations; the agreement between the results of these two approaches is found to be very satisfactory. Also the theoretical and simulated correlation factors, determining the coefficient of tracer diffusion, are always found to agree within a few percent. At small jump rate ratios, the mean-square displacement exhibits an intermediate tβ power-law behavior, with 1/2<β<1, resulting from an incomplete changeover to a purely one-dimensional t1/2 power law.