Nonadiabatic transitions in liquid phase reactions. Net electron polarization in radical pair recombination and triplet-radical quenching

Publisher Website
Google Scholar
Abstract
The nonadiabatic transitions leading to the net chemically induced dynamic electron polarization (NCIDEP) in radical–radical (RR) recombination and triplet–radical (TR) quenching are analyzed in detail. The theory treating the transitions induced by both the fluctuating and the nonfluctuating interactions in a unified manner is developed. The discussed nonadiabatic mechanism of NCIDEP generation can be considered as an extension of the well‐known ST−‐mechanism. Simple analytical formulas for NCIDEP are derived which are applicable in different regions of parameters of the model suggested. It is shown that the fluctuating (anisotropic) hyperfine interaction (hfi) can make significant contribution to NCIDEP RR‐recombination which is comparable with the contribution of nonfluctuating (isotropic) hfi. The fluctuating zero‐field splitting interaction dominates the generation of NCIDEP in TR‐quenching. Contribution of the fluctuating interaction appears to strongly depend on the correlation time of fluctuations. Theory predicts essentially different dependencies of the contributions of fluctuating and nonfluctuating interactions on the viscosity of a solution. The difference can easily be distinguished experimentally.