Stability and fragmentation of OCS²⁺ studied by using auger-electron-ion coincidence measurement

An Auger-electron-ion coincidence method has been applied to investigate dissociation of OCS²⁺ states with two valence holes, which are populated via Auger decay following S 2p photoionization of OCS. We found that OCS²⁺ states lying around a binding energy of 32 eV are mostly stable against dissociation, which indicates that the potential energy surfaces of these OCS²⁺ states have deep wells around the Franck-Condon region. In contrast, the OCS²⁺ states lying around 34 eV and 42 eV dissociate predominantly into CO⁺ + S⁺ and O + C⁺ + S⁺, respectively.