© 2017 American Chemical Society. The fragmentation dynamics of predissociative SO 2 (C̃ 1 B 2 ) is investigated on an accurate adiabatic potential energy surface (PES) determined from high level ab initio data. This singlet PES features non-C 2v equilibrium geometries for SO 2 , which are separated from the SO(X̃ 3 Σ - ) + O( 3 P) dissociation limit by a barrier resulting from a conical intersection with a repulsive singlet state. The ro-vibrational state distribution of the SO fragment is determined quantum mechanically for many predissociative states of several sulfur isotopomers of SO 2 . Significant rotational and vibrational excitations are found in the SO fragment. It is shown that these fragment internal state distributions are strongly dependent on the predissociative vibronic states, and the excitation typically increases with the photon energy.