“…The idea was originally explored by several workers, including Rabinowitch [36], who proposed that the characteristic time of a process can be defined as the sum of the characteristic time of the reaction act and the characteristic time for reactants to diffuse toward each other. In the simple case of a first-order reaction, the characteristic times can be replaced with the reciprocal rate constants 20) where k ef , k, and k D , respectively, are the effective, reaction, and diffusion rate constants.…”