Monte-carlo simulation of the oscillatory dynamics of a catalytic reaction with lateral interactions

Abstract

We consider a stochastic simulation model of the NO+CO reaction on the (100) face of a platinum single crystal. We investigate the mechanism that gives rise to self-exciting oscillations at the micro level. The system dynamics is calculated using the multilevel kinetic Monte-Carlo method in real time. A grid with several millions of points is used. We show that the reason for the appearance of oscillations is lateral interactions in the adsorbate layer, which speed up the reaction and slow down the desorption processes. The reaction occurs in the form of a periodic surface explosion; as a result, the adsorption layer either fills almost the entire surface or is almost completely stripped from the surface. We investigate the effect of the migration rate on the realization of kinetic oscillations in the microscopic model. Analysis of films from the surface of the lattice model has shown that in the course of the observed reaction "eddies" are constantly born and destroyed in different parts of the surface. With certain special initial conditions, the model leads to excitation of plane traveling and spiral waves.