Equation-free multiscale computations for a lattice-gas model: coarse-grained bifurcation analysis of the NO plus CO reaction on Pt(100)

Using the recently developed coarse timestepper approach (Proc. Nat. Acad. Sci. USA 97 (2000) 9840) we study a lattice-gas model of the NO+CO/Pt(1 0 0) reaction exhibiting macroscopic bistability and kinetic oscillations. Through numerical continuation and stability analysis, we construct one-parameter coarse bifurcation diagrams and contrast the results of mean-field differential equation models with the coarse-grained, expected dynamics of kinetic Monte Carlo (kMC) lattice-gas model simulations. We show how our computational superstructure enables the direct kMC simulator to perforin tasks, such as continuation and numerical bifurcation analysis, for which it has not been originally designed. This closure-on-demand approach trades function evaluations with estimation based on short, appropriately initialized kMC simulations. We discuss its scope in complex/multiscale system modeling and simulation. (C) 2004 Elsevier Ltd. All rights reserved.