CRITICAL EXPONENTS FOR THE IRREVERSIBLE SURFACE-REACTION A PLUS B -] AB WITH B DESORPTION ON HOMOGENEOUS AND FRACTAL MEDIA

A model for the surface reaction A + B --> AB with B desorption exhibits a continuous irreversible phase transition from an A-poisoned state to a reactive regime. At criticality, an empty patch embedded in the poisoned state spreads on the sample following a random-walk diffusion behavior. So, a relationship between dynamic exponents of the reaction process, the random-walk exponent, and the fractal dimension of the substrate is conjectured and tested.