Translational spectroscopy of neutralization-reionization double-collision processes of Ar+ ions at keV energies

Reionization agents for neutralization-reionization mass spectrometry

“…Table I data are generally similar to the target efficiencies found for charge stripping (17)(18)(19) and for reionizing small fast neutrals (9,(20)(21)(22)(23). Although oxygen is the optimum target for all three fast neutrals tested, these show significant differences in relative efficiencies, as do the other neutral species of Table II.…”

“…Similarly, fast alkali-metal atoms are ionized with target efficiencies 02 > N2 > H2 (20,21). For fast Ar reionization 02 has superior efficiency (22,23), while for fast He2, H3, ND4, and N2D7 Porter and Gellene (9) have recently shown the relative efficiencies to be N02 > 02 > N2 > He. Other NRMS experiments have utilized helium (3, 4, 6-8,10-12) and H2, N2, Ar, Kr, and Xe (24) for reionization, with our most recent work (13,14) utilizing oxygen, as recommended here.…”

Neutralization agents for neutralization-reionization mass spectrometry

“…Effect of Kinetic Energy on Neutral Flux. The variation of charge-exchange cross section with kinetic energy has been well-studied over a wide energy range for many simple systems (5)(6)(7)(8)(9)(10). Although symmetric resonant processes such as H2°+ H2+• generally show a decrease in cross section with increasing kinetic energy, that for unsymmetric nonresonant cases, i.e., unlike ions and targets, increases with increasing energy to a maximum, then decreases.…”

“…An extension of this method, termed neutralization-reionization mass spectrometry (NRMS) (3,4) incorporates the methodology of Gellene and Porter (5) for the alternative preparation of the fast neutrals by charge exchange of mass-selected precursor ions. Similar experimental techniques have studied electron transfer and energy states of simple mono-to triatomic species such as H3 (5)(6)(7)(8)(9)(10). NRMS makes possible the preparation of neutral species whose reference reionization mass spectra can be directly compared to those of neutral dissociation products.…”

Neutralization-reionization mass spectrometry (NRMS)

“…In general, the soft targets are also those capable of accepting an electron in the reionization process (eq 4), a reaction that should have a lower energy requirement than eq 3 and produce reionized species of lower average internal energy. 44 To illustrate, in the NR spectra of CH3COCH3*+ (Figure 5) the increase in fragmentation is dramatic upon changing the reionizing target from 02 to He.…”