Optically detected proton and nitrogen ENDOR in the ³E_u state of zinc porphine in an n-octane single crystal

Abstract

Via optically detected ENDOR the hyperfine tensors of the protons, and partially of the nitrogen atoms, of zinc porphine in its ³ E_u 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 b_1g symmetry has to be included in order to arrive at a consistent interpretation. The spin densities are compared with calculations and confirm a (e_g ← a _2u ) orbital configuration for ZnP in its ³ E_u state.