A LATTICE-GAS MODEL FOR HALIDE ADSORPTION ON SINGLE-CRYSTAL ELECTRODES

A lattice-gas model is described for the adsorption of halides on sing le-crystal electrodes. The lateral interactions between the adsorbed h alides include a short-range nearest-neighbor interaction and a long-r ange electrostatic interaction. By Monte Carlo simulations the model i s used to fit the experimental isotherm of bromide adsorption on Ag(10 0), giving information about the relative importance of the long-range and short-range interactions. The model reproduces the order-disorder transition observed experimentally, and the way in which the long-ran ged interactions influence the properties of this phase transition is discussed. The Monte Carlo simulations are also compared to analytical mean-field and quasi-chemical approximations to the isotherm. Finally , the kinetics of the disorder-order transition are studied by dynamic Monte Carlo simulations, and some results on isotherms and ordered ph ases on (110) and (111) surfaces are described. (C) 1998 Elsevier Scie nce S.A. All rights reserved.