Derivation of molecular spectra from the polarized spectra of monoclinic crystals and its application to the electronic spectrum of bis(methoxyacetato)diaquacopper(II)

Abstract

A method of determining the molecular absorption tensor of molecules having a single symmetry axis (pointgroups C_s, C₂ and C_2h) and crystallizing in a monoclinic space group is described. The method is applied to the electronic spectrum of bis(methoxyacetato)diaquacopper(II) and shows that the “d–d” electronic transitions are polarized approximately midway between the bond directions and the bisectors of O[graphic omitted]O bond angles, probably closer to the bond bisectors, with the most intense absorption occurring when the electric vector lies within theche late ring. A possible explanation for this is considered. The method is also used to derive the g-tensor of the molecule and the non-coincidence of the principal in-plane g-axes and absorption directions is discussed.