Journal of Statistical Physics, Vol. 114, Nos. 1/2, January 2004, p. 101-114.
Lattice-gas models for CO oxidation can exhibit a discontinuous nonequilib-rium transition between reactive and inactive states, which disappears above a critical CO-desorption rate. Using finite-size-scaling analysis, we demonstrate a crossover from Ising to mean-field behavior at the critical point, with increasing surface mobility of adsorbed CO or with decreasing system size. This behavior is elucidated by analogy with that of equilibrium Ising-type systems with long-range interactions.