Electric field induced dissociation of molecules in Rydberg-like highly vibrationally excited ion-pair states

The energetic thresholds for ion-pair photodissociation of diatomic oxygen [O-2 + h nu --> O+ + O-(P-2(3/2), P-2(1/2))] were measured using a novel technique. The technique depends on the production and selective detection of highly vibrationally excited ion-pair states which last for at least 5 mu s following single photon excitation from the ground electronic state of O-2. These ion-pair states are analogous to Rydberg states, and they may be dissociated by an electric field in a similar manner to the field ionization of high principal quantum number Rydberg states, allowing for their selective detection. [S0031-9007(97)04265-8].