Semiempirical Molecular Orbital Calculations. I. The Electronic Structure of H2O and H2S

The results of calculations of the molecular orbitals of H2S and H2O are reported. The molecular orbital energies were obtained at the self-consistent charge distribution, from the secular equation |Hij−EGij|=0.An open-shell treatment of the oxygen and sulfur p orbitals was used, together with the relationship, Hij=(2−| Sij | )(Hii+Hjj)Gij/2 for the resonance integrals. The orbital energies agree very well with those from ab initio calculations and the method should prove useful with larger molecules where a more sophisticated treatment is not feasible.