Transition rates in a stochastic medium

A description of noise-induced reaction rates in a fluctuating medium is presented. The environment is assumed to exist in a number of distinct configurations and transitions between these configurations are governed by a Markov process. The environment fluctuations drive transitions between reactant and product regions described by a set of generalized coordinates. General expressions for the rate coefficients are presented and illustrated for a reaction driven by dichotomous switching between fixed-point and limit-cycle states.