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 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 SbO2 give the lowest quartet state, an (a) over tilde (4)A(1) state, with a T-e of 53.7 kcal mol(-1) (2.33 eV). Reliable ionization energies to the (a) over tilde B-3(2) and (b) over tilde (3)A(2) states of SbO2+ and vertical excitation energies from the (X) over tilde (2)A(1) state of SbO2 to low-lying doublet and quartet states have also been computed to assist future spectroscopic identification of SbO2. (c) 2006 Elsevier B.V. All rights reserved.