Magnetic-field effect on the micellar surface-bound benzophenone tetracarboxylic acid–sodium salt in aqueous cetyltrimethylammonium bromide medium

The effect of an external magnetic field on the spin evolution of the radical pair (RP) photo-generated from the micellar surface-bound benzophenone tetracarboxylic acid sodium salt (BPD) and cetyltrimethylammonium bromide (CTAB) by H-abstraction has been investigated. BPD in SDS or TX100 micellar media does not exhibit any MFE but, in CTAB micellar medium, the RP decay rate and the yield of escape radicals gradually increase with increasing field and ultimately reach saturation. The magnetic field dependence of escape yields and decay rates are systematised in terms of the relaxation mechanism due to anisotropic HFI [δ(hfi)]. At high fields, however, a saturation in the MFE is observed which has been ascribed to the predominance of the escape process.