A non-thermal lattice gas model for a dimer-trimer reaction on a catalytic surface: A computer simulation study

The kinetics of an irreversible dimer-trimer reaction of the type 3A2 + 2B3 → 6AB have been studied using a non-thermal (precursor mechanism) model on a square as well as on a hexagonal lattice surface by Monte Carlo simulation. When the range of the precursors (A atoms) is increased, the model gives production rates (reactive window widths) that are quite large as compared with those for thermal (Langmuir-Hanshelwood mechanism) model. The phase diagrams qualitatively resemble with the standard ZGB model except that the continuous transition point is eliminated when the range of the precursors is extended up to the third nearest neighbourhood. The diffusion of A atoms on the surface as well as their desorption from the surface with a certain probability is also considered to see their effects on the reaction mechanism.