Long-time tails in the kinetics of reversible bimolecular reactions.

A new approach is developed to study the relaxation of concentrations to equilibrium in reversible bimolecular reactions. For A+B <==> C, a general analytic expression is derived for the amplitude of the power law (t(-d/2)) asymptotics for arbitrary diffusion coefficients and concentrations of the reactants. Our formalism is based on the analysis of the time correlation functions describing the equilibrium fluctuations of the concentrations. This powerful and simple procedure can be readily used to study other bimolecular reactions such as A+B <==> C+D.