A MONTE-CARLO ESTIMATION OF SURFACE-DIFFUSION BY SIMULATING LASER-INDUCED THERMAL-DESORPTION

A current method of experimentally estimating surface diffusion is laser-induced thermal desorption (LITD). We consider the behavior of adsorbed species such as hydrogen on a (111) face-centered-cubic surface of platinum or rhodium. The diffusion coefficients for a variety of systems and surface coverages are estimated by the simulation of a laser-induced thermal desorption experiment. Novel Monte Carlo methods are used that eliminate the time conversion difficulties that arise when using a standard Metropolis algorithm. In particular, the process of adsorbate hopping is determined strictly on the basis of local configurations of adsorbed particles. The results from the simulation are favorably compared to experimental data and provide estimates of the diffusion parameters for the studied systems. © 1990 American Institute of Physics.