Production of Rg+ ions in the resonance-enhanced multiphoton ionization spectroscopy of Rg · NO (Rg = Ar, Kr and Xe) Original Research Article

The observation of rare gas cations (Rg+) in the multiphoton ionization of Rg · NO is studied. Kr+ and Xe+ are produced when exciting via the à state of Rg · NO, addition to Rg · NO+. In contrast, only Xe+ is seen when exciting via the C̃ state of Xe · NO, and only Kr · NO+ is seen when exciting via the C̃ state of Kr · NO. Ar+ is not seen when exciting via either the à or C̃ states of Ar · NO. The production of the different ions is studied as far of laser power by altering the laser intensity and focusing conditions. For excitation via the à state of Kr · NO, it is found that Kr+ production is favoured by high laser intensities, with Kr · NO+ being favoured by low intensities. Under tight focusing conditions for the one-colour experiments on Kr · NO, Kr+ ions are also produced on NO A ← X resonances. Two-colour experimenrs are also performed on Kr · NO. The observation of Kr+ on Kr · NO resonances is explained by intracomplex photoinduced charge transfer within the core of a Rydberg state, with collisional charge transfer between NO+ and Kr · NO also playing a role. The production of Kr+ on NO resonances is explained by photoinduced collisional charge transfer.