Evidence for quasibound states in highly excited CO+ and NO+

Quasibound rovibronic states in CO⁺ and NO⁺ with excitation energies of more than 20 eV are formed in charge-exchange reactions of CO²⁺ and NO²⁺ with alkali atoms. The kinetic energy released upon dissociation is measured by using translational spectroscopy. A new and simple device is presented to determine which fragment holds the charge. A large number of quasibound states is found, spread over all dissociation limits. The complexity of the spectra prevents a full interpretation of all structures. The absence of long-lived vibrationally excited states in CO²⁺, which was predicted theoretically is corroborated.