Partially diffusion-controlled recombination

We extend Tachiya’s method for treating totally diffusion-controlled recombination of a pair of particles to partially diffusion-controlled recombination. The differential equation satisfied by the survival probability of the pair is derived, and solved for several cases of practical interest. Recent experiments on the solvated electron yield in liquid ammonia are analyzed by use of the present theory. It is confirmed that the rather high yield of solvated electrons in irratiated liquid ammonia is due to the slowness of the recombination reaction e−s+NH+4.