A modified INDO-MO study of electronic spectra of open-shell transition metal complexes

Abstract Parameters of a modified INDO-type MO method are presented for transition metal complexes. By use of these parameters, Longuet-Higgins and Pople type RHF-MO calculations were performed for such open-shell complexes as CuCl 4 2− and MOX 5 n − (M = V(IV), Cr(V), Mo(V), W(V), or Re(VI); X = F − , Cl − , or Br − ). The electron distribution obtained for Cucl 4 2− was almost the same as that obtained with a previous ab initio MO calculation. Calculated transition energies for these complexes agreed fairly well with experimental ones, and reasonable assignments were obtained with some exceptions. This method also gave reasonable results on spin densities and bonding natures. Further MO calculations were carried out for some closed-shell transition metal complexes. Reasonable results were obtained for the transition energies and assignments.