Pattern formation for NO+NH3 on Pt(100): two-dimensional numerical results.
The Lombardo-Fink-Imbihl model of the NO+NH3 reaction on a Pt(100) surface consists of seven coupled ordinary differential equations (ODE) and shows stable relaxation oscillations with sharp transitions in the relevant temperature range. Here we study numerically the effect of coupling of these oscillators by surface diffusion in two dimensions. We find different types of patterns, in particular phase clusters and standing waves. In models of related surface reactions such clustered solutions are known to exist only under a global coupling through the gas phase. This global coupling is replaced here by relatively fast diffusion of two variables which are kinetically slaved in the ODE. We also compare our simulations with experimental results and discuss some shortcomings of the model.
Uecker
Hannes
H
Mathematisches Institut I, Universität Karlsruhe, D-76128 Karlsruhe, Germany. hannes.uecker@math.uni-karlsruhe.de