PHOTOSEPARATION OF ION RADICALS FOLLOWING EXCIPLEX FORMATION AND SPIN CONVERSION

Assuming that exciplexes are formed from solvent-separated ion pairs that are subjected to singlet−triplet conversion, we calculated the exciplex fluorescence and ion−radical separation quantum yields. Analytical expressions for both were obtained within the contact approximation for ion recombination to the excited triplet state. The spin conversion affects the competition between exciplex formation and charge recombination if their rates are not equal. The effect significantly depends on the initial separation of photochemically generated ion pairs and the rate of spin conversion that can be changed with the external magnetic field.