MOLECULAR-DYNAMICS SIMULATIONS OF A PROPAGATING CHEMICAL WAVE-FRONT

The propagation of a chemical wave front in a nonhomogeneous system wi th a model reaction A + B --> A + A is simulated using periodically ex panded molecular dynamics technique for reactive hard spheres. It is s hown that for fast reactions the speed of a front does not depend on t he rate constant as the standard, parabolic reaction-diffusion equatio n predicts and its value scaled by the square root of the rate constan t k is an increasing function of k. This phenomenon may be explained o n the basis of extended irreversible thermodynamics if separated equat ions for the concentration of A and for the associated diffusive flow of A are considered.