Valence orbital energies of some second-row elements in excited configurations

Abstract

Although the 3d orbital of a second-row element in a configuration sp^mdⁿ(n 2) is now known to be comparable in size with the other valence orbitals, its energy is extremely small. Results of numerical SCF calculations are presented to support this contention. These also show that the application of Koopmans theorem in such cases is invalid.

The cause for the disparity in the valence orbital energies is traced to the effective potential energies which the valence electrons experience. A comment is made upon a mechanism by which 3d orbitals might engage in the bonding of second-row elements in high oxidation states.