TRANSIENT ORDERED STATES IN A MODEL REACTION ON A SURFACE WITH ACTIVE SITES

Abstract

A model for the monomer–monomer surface reaction of the type A + B → AB, with diffusion of A and B monomers on a surface and reaction only on active sites randomly distributed on the surface, has been proposed and studied. For a critical point where both adsorption probabilities are the same, a seemingly reactive steady state transforms itself into a poisoned state. In this transient state, the production of AB molecules, in relation to the density of active sites, is considered and an inert-reactive irreversible phase transition is observed. The critical values of the density of active sites, where the irreversible phase transition occurs, is obtained in the limit L → ∞ by means of a finite-size scaling analysis. The critical exponents that dominate the correlation length of clusters, as well as the production of AB molecules at criticality, are determined.