Neutralized ion-beam studies of the rare gas hydrides: Observation of unique metastability for NeH

Abstract

The rare gas hydride radicals have been produced by charge exchange of the corresponding ion in a mass selected, high velocity beam with K, Na, Mg, Zn, or Hg target metals. NeH shows unique behavior, being produced in both dissociative and long-lived (>5.0 μs) metastable states. Arguments based on energetic considerations are presented that the observed metastability should be associated with the ground state of the NeH radical, requiring that it have a shallow well and dissociation barrier analogous to those previously determined for the ground states of the isoelectronic NH4, H3O, and H2F radicals. The existence of a structured radiative transition near 6.1 eV is predicted for the NeH radical. The other rare gas hydrides exhibit only dissociation of the radical with the kinetic energy released explainable in terms of production of known electronic states of the radicals by near resonant electron transfer. For HeH and ArH the first excited electronic state (A 2Σ+) is observed to efficiently predissociate into the repulsive ground state, whereas for KrH and XeH, lower limits of 4.5 and 3.9 eV, respectively, are determined for the energies of the corresponding excited states with respect to the separated ground state atoms.

Effects of confinement on the Rydberg molecule NeH

“…A number of experimental techniques have been developed to generate atoms and molecules in Rydberg states and to determine their properties (see, e.g., [22][23][24][25]). Fieldionization [26] is an efficient method for detecting Rydberg molecules and measuring their energy levels.…”

The emission spectrum of helium hydride. IV. Bands near 4100 and 4600 Å

“…The decay of the n=2 Rydberg states of NeH was investigated by translational spectroscopy. [30][31][32]49 Ab initio calculations on bound excited states have so far been performed for all rare gas hydrides except XeH: HeH (see above and paper I), NeH,15,[33][34][35][36][37][38]36,[38][39][40][41][42][43] They were very helpful for the assignment of the observed spectra and agree well with the experimental results.…”

Studies of Unusual Simple Molecules by Neutralization-Reionization Mass Spectrometry

“…'H3 have lifetimes Many radical species have now been studied by NRMS. A 1987 ctronic (Rydberg) review (10) (37). the atmospheric oxidation ofSO2) (52), CH3SO`, CH2SOH (intermeis found not to be diates in the biological and atmospheric oxidation of sulfur com-.H5+ (and CD5+) pounds) (18), and SF5 (30).…”