MAGNETIC-FIELD EFFECTS IN THE PRESENCE OF A CAGE EFFECT

The manifestations of the cage effect between different magnetic field effects in radical pair (RP) recombination reaction in liquids are di scussed. Recently it has been shown that a relatively strong attractiv e potential with a potential well results in a long lived intermediate state of diffusive RP. This state can be interpreted as the cage. A s imple and accurate approximation for the calculation of kinetics of ma gnetic field dependent geminate RP recombination in the presence of a cage effect is proposed. The theoretically predicted kinetics in the p resence of the cage effect is shown to describe recent experimental re sults on geminate RP recombination in viscous liquids much better than the free diffusion model. The multiplet CIDEP spectra of radicals are also shown to be sensitive to the presence of the cage effect. These spectra are specially sensitive for highly asymmetric RPs [with essent ially different values of hyperfine interaction (hfi)]. In particular, the multiplet CIDEP spectrum of the radical with the weaker hfi's can change it's sign as the cage life time is changed. The results of som e recent CIDEP measurements of geminate RP recombination are in very g ood agreement with the predictions of the cage model.