ON KINETIC PHASE-TRANSITION OF THE DIMER-MONOMER REACTION MODEL

A detailed mean field theory (MFT) based on pair approximation (PA) is constructed to illustrate the kinetic phase transition behavior of th e dimer-monomer surface reaction model A+1/2B(2)-->AB and its variants which take into account diffusion and desorption of both adsorbed spe cies, Eley-Rideal reaction step, finite reaction probability and ''end on mechanism'' for B-2 adsorption. We find that the PA-MFT can reprodu ce well the phase diagrams and yield quite good predictions of the eff ects of diffusion, desorption etc., which indicates that PA-MFT may be suitable for the description of the steady state behavior of this mod el. (C) 1997 Elsevier Science B.V.