Theoretical and experimental studies of chemically induced dynamic nuclear polarization kinetics in recombination of radical pairs by the method of switched external magnetic field. II. ~(13)C CIDNP of micellized radical pairs

摘要

The method of ~(13)C chemically induced dynamic nuclear polarization in a switched external magnetic field (SEMF CIDNP) has been applied for the first time in an experimental investigation of micellized radical pairs (RP). Using the examples of three photochemical reactions it has been shown, that SEMF 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 previously developed theory [Parnachev et al., J. Chem. Phys. 107, 9942 (1997)]. It has been demonstrated that such an analysis provides information on the rates of radical escape from the micelle, on electron relaxation and on the rate of S-T_ transitions. The analysis of the estimated rates of S-T_ transitions showed that the exchange interaction is essentially anisotropic in the RPs studied.