Charged-particle production in low-energy H+H2 and H+He collisions

Abstract

Absolute cross sections for producing H+, H−, H+2, He+, and e− have been measured for fast hydrogen atom impact on H2 and He targets. The hydrogen atom energy ranged between 50 eV and 3.0 keV. For the H+H2 reaction, the dominant ion-formation process for hydrogen atom energies below 250 eV was found to be H−+H+2 production. For He targets, production of H+ dominated over the entire hydrogen atom energy range. The results are compared, where possible, with the data of other investigators and are discussed in terms of possible reaction mechanisms.

Cross sections for electron capture and loss by H+ and H impact on O and O2

“…Here their cross sections can exhibit surprisingly detailed structures as a function of H‐atom energy. We have found such striking behavior for H‐atom impact on Ar [ Van Zyl et al , ], N 2 and O 2 [ Van Zyl et al , ], H 2 [ Van Zyl et al , ], and other H atoms [ Gealy and Van Zyl , ], down to H energies of only 0.05 keV. But such structures persist down to even lower H energies, as nicely shown for rare‐gas‐atom targets by Aberle et al [].…”

“…As can be seen, the differences between the two data sets are very similar to the differences in the σ A /σ M ratios shown in Figure b. The σ 01 for both O and O 2 targets exhibits a rather smooth and rapid decrease with decreasing H‐atom energy, so typical of such ionization‐stripping reactions [ Van Zyl et al , ; Van Zyl et al , ; Van Zyl et al , ; and Gealy and Van Zyl , ].…”

“…In contrast, the σ 0–1 data show evidence of departures from such smooth and rapid decreases with the appearance of upward inflections at the lower H‐atom energies. However, the slight upward inflection found for O 2 targets (dashed‐line curve) is much less prominent than for N 2 or H 2 targets [ Van Zyl et al , ; Van Zyl et al , ]. Although the O‐atom‐target data indicate a somewhat larger inflection than those for O 2 , it nevertheless is not nearly as prominent as that found earlier for H + H collisions [ Gealy and Van Zyl , ].…”

Collisional kinetics of non-uniform electric field, low-pressure, direct-current discharges in H2

“…Figure 15(b) shows cross sections for H − production used in the model of H 2 discharges in this paper. The projectiles and the associated references utilized are H [72,73,74] [15]. In several beam type experiments, a two-step process leading to H − is observed [80,81,82].…”

A simulation study of a windowless gas stripping room in an E//B neutral particle analyzer

“…By introducing a global charge state variable in the hadron reaction physics, the charge state of H and D is recorded when the charge exchange reaction happened in the gas stripping chamber. Many charge exchange cross section measurements have been performed for H on H 2 gas during the last century [43][44][45][46][47][48][49][50][51][52][53]. Fig.…”