GROUND AND LOW-LYING EXCITED-STATE PROPERTIES OF THE FIRST-ROW TRANSITION-METAL OXIDE DIATOMICS CALCULATED BY AN IMPROVED ASED-MO MODEL

The ground and selected low-lying electronic states of the entire seri es of the first-row transition-metal neutral oxides are investigated b y the use of an improved atom superposition and electron delocalizatio n molecular orbital (ASED-MO) approach. Two quantities are found to be very important in achieving agreement with experiment: these are the (kappa,delta) parameter set - involved in the Wolfsberg-Helmholz const ant, K - and the charge dependent Slater-type orbital exponents. For S eO through CrO the optimum (kappa,delta) set of (0.87, 0.24 Angstrom(- 1)) yields ground states and spectroscopic constants (R(e), D-0, omega (e) and mu) in good agreement with experiment. The set (1.00, 0.35 Ang strom(-1)) works well for MnO to CuO and (0.75, 0.13 Angstrom(-1)) for ZnO. Calculations are consistent with both ionic and covalent bonding contributions in the monoxides. The M-O bond strengths exhibit the '' double humped'' shape, characteristic of many periodic properties of t he transition metals. Moreover, the sharp contrast in the calculated b ond energies between the early and late transition-metal oxides accoun ts well for the pronounced differences in their reactivities.