Semi-empirical molecular orbital calculations on ruthenium(III) and rhodium(III) octahedral complexes

Abstract

Semi-empirical Wolfsberg-Helmholz molecular orbital (WHMO) calculations were performed on some octahedral complexes of second-row transition ions employing the approximations of (i) Basch and Gray and (ii) Cotton and Harris, for calculating the valence orbital ionization potentials (VOIP's) of the metal. A critical analysis indicates that the latter approximation gives better results in general. A charge dependence of the overlap was found to be necessary when the self-consistent charges were not very close to integral numbers. An attempt has also been made to interpret the optical spectra of these complexes. The rhodium complexes exhibit crystal-field bands while there is considerable overlapping of crystal-field and charge-transfer bands in the ruthenium complexes.