KINETICS OF THE MONOMER-MONOMER SURFACE-REACTION MODEL

The two-dimensional monomer-monomer (AB) surface reaction model withou t diffusion is considered for infinitesimal, finite, and infinite reac tion rates k. For equal reactant adsorption rates, in all cases, simul ations reveal the same form of slow poisoning, associated with cluster ing of reactants. This behavior is also the same as that found in simu lations of the two-dimensional voter model studied in interacting-part icle systems theory. The voter model r-an also be obtained from the di mer-dimer or monomer-dimer surface reaction models with infinitesimal reaction rate. We provide a detailed elucidation of the slow poisoning kinetics via an analytic treatment for the k = 0+ AB reaction and the voter models. This analysis is extended to incorporate the effects of place-exchange diffusion which slows, but does not prevent poisoning. We also show that the k = 0+ AB reaction with no diffusion is equival ent to the voter model with diffusion at rate 1/2. Identical behavior of the monomer-monomer reaction and the voter model is also found in a n ''epidemic'' analysis, where one considers the evolution of a surfac e poisoned by one species, except for a small patch. Finally, we apply our findings to elucidate the behavior of the monomer-dimer surface r eaction model for small reaction rates.