KINETIC PHASE-TRANSITIONS IN A REVERSIBLE UNIMOLECULAR BIMOLECULAR SURFACE-REACTION SCHEME

The model surface reaction scheme A2(g) + 2V reversible 2A(a), B(g) + V reversible B(a), and AB(g) + 2V reversible A(a) + B(a) is studied by Monte Carlo simulation. The effects of adsorption, desorption, and surface reaction are included in the model. For small probabilities of desorption of the reactants A2 and B, a kinetic phase transition in the surface reactivity is found. This phase transition occurs only when the probability of desorption of A2 is significantly larger than that of B. A mean field analysis predicts a phase transition over a somewhat wider range of desorption probabilities than the Monte Carlo simulation results indicate.