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 [O₂+hν→O⁺+O^-(²P3/2,²P1/2)] 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 5μs following single photon excitation from the ground electronic state of O₂. 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.