Perturbation of particle velocity distribution in a bistable chemical system

Departure from Maxwellian particle velocity distribution induced by chemica l reactions is studied in a bistable homogeneous system maintained out of c hemical equilibrium. In the vicinity of the bifurcation associated with the coalescence of two stationary states, the dynamics of the system is very s ensitive to small perturbations originating from the deformations of partic le velocity distribution. An analytical approach of Boltzmann equations and microscopic simulations show that the perturbation of velocity distributio n results in a significant deformation of the bifurcation diagram. (C) 1999 Published by Elsevier Science B.V. All rights reserved.