Nonequilibrium distribution function formalism for diffusion-influenced bimolecular reactions: Beyond the superposition approximation

We introduce an improved and systematic procedure for solving the diffusion -influenced reaction kinetics problem based on a hierarchical set of kineti c equations for many-particle distribution functions. As a representative e xample, we apply the formalism to the reversible association kinetics probl em. The new method gives an approximate analytic solution which is in almos t perfect agreement with the Brownian dynamics simulation results for the w hole time range. It is shown that results of previous nonequilibrium distri bution function theories are reproduced as lower order solutions in the pre sent formalism. (C) 1999 American Institute of Physics. [S0021-9606(99)5042 2-4].