KINETIC PHASE-TRANSITIONS AND BISTABILITY IN A MODEL SURFACE-REACTION.2. SPATIALLY INHOMOGENEOUS THEORIES

We introduce a general framework for describing surface reactions whic h can be used to understand spatially inhomogeneous states. This theor y is applied to reactions with and without surface diffusion. Our appr oach gives rise to an infinite hierarchy of equations which in princip le exactly describes the surface reaction. By truncating this hierarch y, tractable approximate theories may be developed. As an example, thi s approach is applied to a simple model of the surface-catalyzed 2A B-2 --> 2AB reaction. We show how the metastability and nucleation phe nomena which occur in the vicinity of the A-poisoning transition for t he diffusionless reaction may be modeled. The effect of allowing one s urface species to diffuse is also examined.