TRANSITIONS IN THE KINETICS AND STEADY-STATES OF IRREVERSIBLE A-REACTION MODELS(BC SURFACE)

The three-component irreversible surface-reaction model A + BC --> AC + 1/2B2 with infinite reaction rates between nearest-neighbor adspecie s is studied by Monte Carlo simulations. For a square lattice the syst em evolves to a degenerate poisoned state exponentially in time, excep t for a narrow range of pressures in which a reactive quasi-steady-sta te exists. The latter poisons very slowly in time. For a hexagonal lat tice a true reactive steady state occurs for a range of pressures bord ered by continuous and discontinuous transitions to poisoned states. T he latter behavior is observed by adding the reaction channel A + B -- > AB on a square lattice. Some properties of these models are elucidat ed by analysis of appropriate exact master equations and corresponding pair approximations. Other issues addressed include ''extent of varia bility'' of the degenerate poisoned states, the effect of finite react ion rates, and spatial correlations.