A Monte Carlo study of surface diffusion coefficients in the presence of adsorbate–adsorbate interactions. I. Repulsive interactions

Chemical, jump, and tracer diffusion coefficients, D, Dj, and D*, respectively, for the case of nearest-neighbor repulsive interactions have been determined by Monte Carlo simulations on a fixed square lattice. D was determined by the fluctuation autocorrelation function method and from the Kubo–Green equation, using values of 〈(δN)2〉/〈N〉 determined from isotherms. It was found that the two methods give essential agreement over the entire coverage and temperature range examined, 0.73≤T/Tc≤7.33, 0.1≤θ≤0.8. The changes in activation energies for D, D*, and Dj as function of T and θ were determined and can be understood in terms of the phase diagram of the system.