Vibronically-allowed d-d transitions and the magnetic circular dichroism of Cu²⁺ complexes

Abstract

Measurements of the magnetic circular dichroism (M.C.D.) spectra of Cu(NH₃)₄ ²⁺, Cu(en)₂ ²⁺ and Cu(gly)₂ ²⁺ at room temperature are described. M.C.D. parameters expected for the vibronically-allowed d-d transitions of tetragonal complexes are calculated, and the observed M.C.D. spectra are analysed and interpreted. Calculations of the vibronically-allowed electric dipole transition moments are made on the basis of the theory proposed by Koide and Pryce. The B term is found to be dominant in the M.C.D. of these Cu²⁺ complexes at room temperature. The contribution of the C term, which is introduced as an effect of spin-orbit coupling, is considered.