Magnetic field effects on the dynamic behavior of a radical pair as studied by a sub-nanosecond laser flash photolysis technique

The hydrogen abstraction reaction of triplet 4-methoxy-benzophenone with thiophenol at 265 K was studied by a sub-nanosecond laser flash photolysis technique in the absence and presence of a magnetic field of 1.75 T. The decay rate of the generated radical pair at zero field was found to be 1.1 × 109 s−1 and that at 1.75 T to be 1.8 × 109 s−1. The observed magnetic field effect can be explained by the acceleration of the triplet–singlet spin conversion process due to the Δg mechanism.