Suppression of Fluctuation-Dominated Kinetics by Mixing

Abstract

Fluctuation effects in diffusion-controlled reactions have attracted much attention since the pioneering works of Ovchinnikov and Zeldovich [1] and of Toussaint and Wilczek [2]. Thus even the simplest bimolecular reaction of A + B -> 0 type does not in general obey classical kinetics, since the long-time decay of the reactants’ concentrations is dominated by fluctuations. It is believed that stirring destroys large fluctuations and therefore restores classical kinetics. Some simple models support this point of view, see Ref.3 for a review. The purpose of the present Chapter will be to show the origin of fluctuation effects, to present a theoretical approach allowing to treat diffusion and stirring on an equal footing and to elucidate the influence of different mixing procedures on the course of the reactions.