Critical behavior of nonequilibrium continuous phase transition inA+BCcatalytic reaction system

Abstract

We study two lattice gas models for the A+BC-->AC+ 1/2 B2 reaction system. Model I includes the influences of the adsorbate diffusion and model II includes the effect of the diffusion and position exchange of B and C atoms. Model I exhibits a continuous phase transition with infinitely many absorbing states from a reactive state to a poisoned state of B and C atoms and a discontinuous transition to a poisoned state of A and B atoms when the fraction of A in the gas phase varies. The critical exponents are estimated accurately. The simulation results indicate clearly that the critical behavior of the continuous phase transition in model I belongs to the directed percolation (DP) universality class. Model II, however, exhibits a continuous transition with two absorbing states, and its critical behavior is obviously distinct from the DP universality class.