The B-2(2), (2)A(2) and B-2(1) ionic excited states of sulfur dioxide were studied by quantum calculations with the density functional theory ( B3LYP functional) and the coupled cluster singles and doubles with perturbative triples [CCSD(T)] methods. The optimized structure of the B-2(2) state was of a transition state correlating to an equilibrium geometry of the C-s point group, contrary to previous studies. The B-2(1) state has two equilibrium structures of a bent and a cyclic geometry. By the computation of Franck-Condon factors, the photoelectron spectrum of the (2)A(2) state was simulated and was found to be in agreement with the experiment, but with different assignments. (C) 2009 Elsevier B. V. All rights reserved.