Optically detected proton and nitrogen ENDOR in the3Eustate of zinc porphine in ann-octane single crystal

Via optically detected ENDOR the hyperfine tensors of the protons, and partially of the nitrogen atoms, of zinc porphine in its 3 Eu state have been obtained. The results show that the in-plane principal axes of the fine-structure tensor make an angle of 7·8 ± 1·1° with the N-N symmetry axes. The spin densities are evaluated from the hyperfine data in a point-dipole model; a nuclear distortion of b1g symmetry has to be included in order to arrive at a consistent interpretation. The spin densities are compared with calculations and confirm a (eg ← a 2u ) orbital configuration for ZnP in its 3 Eu state.