SPONTANEOUS SYMMETRY-BREAKING IN A NO-REACTION MODEL(CO SURFACE)

A simple lattice gas model for the catalytic CO + NO --> CO2 + 1/2 N-2 surface reaction is studied by means of a model involving a stochasti c cluster approximation. The cluster approximation on an infinite squa re lattice gives a reactive interval from a second-order phase transit ion at gamma(1) = 0.171 to a first-order phase transition at gamma(2) = 0.319. The subdivision of the lattice into two chequerboard-like sub lattices leads to a third phase transition at gamma(CO) = 0.227 where the reactive interval ends. This point is the left-hand limit of the d omain of spontaneous symmetry breaking where a phase transition from d ynamical disorder to static order occurs. (C) 1997 Published by Elsevi er Science B.V.