Determination of the kinetic parameters of radical pairs with heavy atom substitutions in micellar solution by optical detected × and Ku band ESR

Abstract

A study is reported of the dynamics of radical pairs formed by the photochemical reaction of benzophenone and its heavy atom substitutions, dichlorobenzophenone and bromobenzophe-none, in a sodium dodecylsulphate micellar solution. Changes were observed in the time profiles of the transient absorptions and in the yields of the escaping radicals induced by the irradiation of an × (9.15 GHz) or Ku band (17.44 GHz) microwave short pulse. From these experiments, the hydrogen abstraction reaction rates, the recombination rates of the singlet radical pairs, the relaxation rates, the escape rates, the decay rates of the radical pairs without the external magnetic field, and the intersystem recombination rates due to the spin-orbit coupling were determined.