Dynamical critical behavior of the Ziff–Gulari–Barshad model with quenched impurities

Abstract

The simplest model to explain the CO oxidation in some catalytic processes is the Ziff–Gulari–Barshad (ZGB) model. It predicts a continuous phase transition between an active phase and an absorbing phase composed of O atoms. By employing Monte Carlo simulations we investigate the dynamical critical behavior of the model as a function of the concentration of fixed impurities over the catalytic surface. By means of an epidemic analysis we calculate the critical exponents related to the survival probability Ps(t), the number of empty sites nv(t), and the mean square displacement R2(t). We show that the critical exponents depend on the concentration of impurities over the lattice, even for small values of this quantity. We also show that the exponents do not belong to the Directed Percolation universality class and are in agreement with the Harris criterion since the quenched impurities behave as a weak disorder in the system.