D. Sundholm et al., FINITE-ELEMENT MULTICONFIGURATION HARTREE-FOCK CALCULATIONS ON THE EXCITATION-ENERGIES AND THE IONIZATION-POTENTIAL OF OXYGEN, The Journal of chemical physics, 96(7), 1992, pp. 5229-5232
The 3P, 1D, and 1S states of oxygen and the 4S ground state of the oxy
gen cation have been studied using large numerical multiconfiguration
Hartree-Fock calculations with systematically increased active spaces.
The nonrelativistic valence limits for the excitation energies are 1.
968 and 4.181 eV for E(3P-1D) and E(3P-1S), respectively. The nonrelat
ivistic valence limit for the ionization potential is 13.593 eV.