AVS 49th International Symposium
    Surface Science Monday Sessions
       Session SS1-MoA

Paper SS1-MoA2
Fluctuations and Bistability in CO Oxidation on Nanoscale Facets

Monday, November 4, 2002, 2:20 pm, Room C-108

Session: Surface Reactions: CO and NO
Presenter: D.-J. Liu, Iowa State University
Authors: D.-J. Liu, Iowa State University
J.W. Evans, Iowa State University
Correspondent: Click to Email
Recent experiments of catalytic surface reactions, especially CO oxidation on nanoscale Pt field-emitter-tips,@footnote 1@ provides tremendous new possibilities for modeling of surface reactions and for comparison with stochastic theories of chemical reactions. Particularly, in a chemical reaction with bistability, fluctuations can induce transitions between the two stable states for sufficiently small systems. We analyze a "hybrid" atomistic model mimicking CO oxidation on nanoscale facets of metal(100) catalyst surfaces. The model, which incorporate infinite CO diffusion and superlattice ordering of immobile O, display bistability for an infinite system. We focus on the probability distribution for the populations of adsorbed species, as well as dynamics of the fluctuations-induced transitions. An effective potential picture emerges from our analyses of kinetic Monte Carlo simulations. Qualitative behavior can be approximated by traditional master equation and Fokker-Planck equations, where the system size dependence and the approach to the critical point can be characterized by the mean-field behavior. Analysis of a generalized model with finite CO diffusion reveals the role of CO diffusion in the crossover from the mean-field to the equilibrium Ising-like behavior. @FootnoteText@ @footnote 1@ Y. Suchorski et al., Phys. Rev. Lett. vol. 82, 1907 (1999).