A COMPARISON OF SPIN EXCHANGE AND CELLULAR AUTOMATON MODELS FOR DIFFUSION-CONTROLLED REACTIONS

Two different lattice models for diffusion-controlled reaction are studied. The first model is based on the Kawasaki spin exchange model and the second is a cellular automaton algorithm based on the Margolus block. Both models have traps present on the lattice which react with the particles diffusing from a source to a sink. Two cases should be distinguished; in the first one, the traps are moving on a time scale much faster than the diffusion (this is the annealed version of the model), in the second case the traps are fixed (this is the quenched version). Theoretical results for the annealed version are presented along with computer simulations (restricted to small trap concentrations) for the quenched models. It is shown that these models are a viable alternative to standard simulations for this class of problem. © 1990.