Laser investigation of the competition between rotational autoionization and predissociation in superexcited np Rydberg states of NO

Rotational superexcited np Rydberg states (n≥23, υ=0) of NO have been state-selectively produced with a two-color double resonance excitation method, and not only the NO⁺ ions generated by autoionization but also nitrogen atoms of the predissociation fragment have been directly detected to investigate the competition between rotational autoionization and predissociation. As a result, it has been found that the predissociation efficiency of the np Rydberg states hardly depends on whether the rotational autoionization channels are open or not. This fact clearly demonstrates that the decay dynamics of these states is governed by predissociation, not by rotational autoionization.