Analysis of the recombination probability of geminate triplet radical ion pairs at single encounter by means of magnetic field effects

The recombination probability of geminate triplet radical ion pairs at sing le encounter alpha has been determined by means of the proposed method of e xperimental data processing based on the Noyes theory regarding the Onsager concept. The method is based on measuring magnitude of magnetic field effe ct in the yield of the geminate recombination products of triplet pairs dep ending on medium viscosity. The method was used to determine alpha for the recombination of geminate triplet radical ion pair {pyrene(-)+N,N-diethylan iline(+)}(3) in methanol. It amounts to 10(-4), which is four orders of mag nitude smaller than that obtained by the standard kinetic method. This is t he basis upon which to conclude that even with the account of Onsager corre ction for polar media the use of Noyes theory for alpha determination is in correct. (C) 2001 American Institute of Physics.