Monte Carlo simulations of ionic adsorption isotherms at single-crystal electrodes

A lattice-gas model is considered for ionic adsorption at single-crystal el ectrodes, the statistical mechanics of which is solved by means of Monte Ca rlo simulations. The model assumes a short-range nearest-neighbor repulsion and a long-range Coulomb repulsion between adsorbed adions. By fitting the model isotherm to the experimental isotherm for bromide adsorption on Ag(1 00), which is lattice-gas-like, some conclusions can be drawn regarding the relative importance of these two interaction channels. Various ordered adl ayers appearing through second-order order-disorder transitions are found o n (100) and (111) surfaces. The inclusion of a simple model for mutual depo larization of the adions leads to first-order phase transitions in the isot herms. Finally some simulations on a uniaxially corrugated (110) surface ar e considered and compared to experimental results of halide adsorption on A g(110). (C) 1998 Elsevier Science Ltd. All rights reserved.