Theoretical and experimental studies of chemically induced dynamic nuclearpolarization kinetics in recombination of radical pairs by the method of switched external magnetic field. II. C-13 CIDNP of micellized radical pairs

The method of C-13 chemically induced dynamic nuclear polarization in a swi tched external magnetic field (SEMF CIDNP) has been applied for the first t ime in an experimental investigation of micellized radical pairs (RP). Usin g the examples of three photochemical reactions it has been shown, that SEM F CIDNP allows the investigation of the kinetics of short-lived micellized RPs with high time-resolution in low and intermediate magnetic fields. The experimental kinetics have been analyzed and simulated on the basis of a pr eviously developed theory [Parnachev , J. Chem. Phys. 107, 9942 (1997)]. It has been demonstrated that such an analysis provides information on the ra tes of radical escape from the micelle, on electron relaxation and on the r ate of S-T- transitions. The analysis of the estimated rates of S-T- transi tions showed that the exchange interaction is essentially anisotropic in th e RPs studied. (C) 1999 American Institute of Physics. [S0021-9606(99)00335 -9].