HETEROGENEOUS CATALYTIC REACTION ON A 2 X-2 LATTICE

We study a model proposed by Fichthorn, Gulari and Ziff for the kineti cs of a generic heterogeneous catalytic reaction; A + B-->AB. This rea ction includes the steps of adsorption and desorption of reactants A a nd B, surface reaction through the Langmuir-Hinshelwood mechanism, and desorption of product AB. We solve the model exactly and without any restriction on a 2x2 lattice. Despite the reduced number of sites empl oyed, the solution shows some of the general features observed by simu lating the mechanism on a large NxN lattice. The rate of reaction depe nds on the rate of desorption of reactants with a maximum at a value s imilar to those found by performing heavy simulations. Also, on a 2x2 lattice; we have coverage of fluctuations of reactants as a Function o f their rate of desorption, as found on large NxN lattices. (C) 1998 E lsevier Science B.V.