Mean reaction times in non-homogeneous kinetics

A kinetic treatment, which is not limited to diffusion processes, is used to evaluate the mean times for the disappearance, reaction and scavenging, or quenching of transient species. The methodology is applied to the kinetics of geminate pair recombination, non-homogeneous radiation chemistry, and fluorescence quenching. At high solute concentrations the mean disappearance time is always dominated by the scavenging or quenching reaction, but at low concentrations the size of the steady-state escaping fraction of the transient species governs whether the 'natural' reaction or the scavenging/quenching process is the primary contributor to the mean disappearance time. Reaction dominates when there is no escape, while the scavenging or quenching dominates when escape is significant.