Computer Simulation Studies of Adsorption of Simple Gases on Alkali Metal Surfaces

Wetting properties of simple gases on alkali metal surfaces are of fundamental importance because they manifest the least attractive gas-surface interactions in nature and because their critical behavior is described by the two-dimensional Ising model. We report simulation results for the adsorption of neon and hydrogen on alkali metal surfaces. These use the grand canonical (classical) Monte Carlo and (quantum) path integral Monte Carlo methods, respectively. We find a set of wetting transitions at temperatures which are very sensitive to the adsorption potentials. Comparison is made with recent experiments and with predictions of a model of Cheng, et al. in which the transition temperature is estimated from a simple cost-benefit analysis involving the surface tension and the adsorption potential.