Collective diffusion in the binary random alloy

In this study, extensive Monte Carlo simulation results are reported on the collective correlation factors (the correlated parts of the phenomenologic al coefficients) in the random binary alloy with the monovacancy mechanism operating at a very small vacancy concentration. It is found that results f rom the analytical formalism of Manning are in excellent agreement with the Monte Carlo results over a very wide range of the ratio of the atom-vacanc y exchange frequencies. Surprisingly, it turns out that the expressions for the collective correlation factors derived in the self-consistent theory o f Moleko ct al. actually simplify to exactly the same expressions as, those of Manning for the binary alloy (although in the case of ternary and highe r multicomponent random alloys the Moleko ct al. formalism provides a diffe rent solution from the collective correlation problem).