The diffusion-influenced reversible geminate-pair recombination problem is solved exactly in one dimension, in the presence of a constant external field. As the field strength changes sign, the long time asymptotics of the components of the Green function solution show a primary kinetic transition, in which the equilibrium values are changed. At two other critical values of the external field the approach to equilibrium changes, from a t(-3/2) power-law to exponential. At the three critical fields, asymptotic t(-1/2) decay prevails. (C) 2001 American Institute of Physics.