Thermochemical and Theoretical Investigations of the Sodium-Oxygen System. II. Properties of NaO and Its Ions from Hartree-Fock Molecular Orbital Studies

Accurate Hartree-Fock wavefunctions, computed by the method of Roothaan, are reported for the 2II and 2Σ states of NaO, for the 3Σ state of NaO+, and for the 3II, 3Σ, and 1Σ states of NaO−. Spectroscopic constants and dipole and quadrupole moments have also been calculated for each of the molecules and ions. Several properties of the Na–O species have been deduced. These properties include the vertical and adiabatic ionization potentials (7.7 and 7.4 eV), electron affinity (1.1 eV), dissociation enthalpy (2.7 eV), several thermodynamic functions for NaO, and the Π 3→Σ1 (1.7 eV) and Π 3→Σ3 (0.2 eV) excitation energies for the NaO− system. Thermodynamic data for selected reactions involving NaO and NaO+ are given, together with a brief discussion of the bond enthalpies in NaO2 and NaO2+.