THEORY OF MAGNETIC-FIELD EFFECTS ON RADICAL PAIR RECOMBINATION IN MICELLES

Magnetic field effects (MFE) of radical pair (RP) recombination in mic elles are investigated both analytically and numerically. The confinem ent effect of a micelle is modeled by a spherically symmetric potentia l well. The results show that the contribution from ST} transitions to all kind of MFEs is significantly increased due to the confinement ef fect. The spin exchange relaxation is also increased causing the ST0-c ontribution to CIDEP to be essentially reduced. Surprisingly a pronoun ced effect of ST+ transitions on CIDNP is found when the confinement i s strong. Simple analytical expressions for the recombination probabil ity and for CIDNP and CIDEP are rigorously derived and a high accuracy is found by comparison with the numerical results. The results are in terpreted in terms of a simple supercage model which is based on the a ssumption that the process can be separated into two stages: (1) a fas t initial germinate stage in which the radicals are thermalised within the micelle and (2) a slower decay of a quasi-equilibrium state by es cape from the micelle.