An ab initio study on some low-lying singlet and triplet states of SbO2+ and quartet states of SbO2

RCCSD(T) calculations on low-lying singlet and triplet states of SbO2+, employing basis sets of up to aug-cc-pV5Z quality, give a linear over(X, ∼)1Σg+state with computed adiabatic and vertical ionization energies of 10.11 and 10.65 eV, respectively. CASSCF/MRCI calculations on low-lying quartet states of SbO2give the lowest quartet state, an over(a, ̃)4A1state, with a Teof 53.7 kcal mol-1(2.33 eV). Reliable ionization energies to the over(a, ̃)3B2and over(b, ̃)3A2states of SbO2+and vertical excitation energies from the over(X, ∼)2A1state of SbO2to low-lying doublet and quartet states have also been computed to assist future spectroscopic identification of SbO2.