5 . 2 . 7 . Nonlinear Dynamics : Oscillatory Kinetics and Spatio - Temporal Pattern Formation

The rate of a catalytic reaction is governed by the underlying mechanism, i.e. the sequence of elementary reaction steps, and depends on the external control parameters such as the concentrations (= partial pressures) pj of educt and product species and temperature T, if transport processes are excluded in this context. More specifically, usually the adsorbed species are assumed to be randomly distributed over the surface, and their concentrations (= coverages) θi are described within a mean-field approximation so that the reaction rate (= number of molecules r formed per unit time, dnr/dtt) is given by