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{sub 2} +h{nu}{r_arrow}O{sup +}+O{sup {minus}}({sup 2}P{sub 3/2}, {sup 2}P{sub 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{sub 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. {copyright} {ital 1997} {ital The American Physical Society}