ENDOR studies on a rotating methyl group

This is the authors' abstract. We don't add key points for this paper.

The radical CH3CHCOOH has been identified by ENDOR measurements as a minor product of the irradiation of succinic acid with x-rays at room temperature. The rotating methyl group gives fairly sharp ENDOR transitions which show second-order splitting. The relative intensities of the transitions suggest a strong relaxation mechanism associated with a time dependent scalar coupling.