Inversion in the magnetic field effect of benzilketyl : SDS radical pair at high fields

The effect of a high magnetic field (up to 13.3 T) on radical pairs generat ed by the hydrogen abstraction of the photoexcited benzil triplet from sodi um dodecyl sulphate has been studied. It was found that both the radical pa ir lifetime and the free radical yield increase with an increase of field f rom 0 to 4 T. A further increase of field causes a decrease in both. This r eversal of the magnetic field effect (MFE) above 4 T has been explained in terms of relaxation mechanism and competition between a number of rate proc esses. The effect of reducing the micelle size on the MFE inversion has bee n discussed. (C) 1999 Elsevier Science B.V. All rights reserved.