Single- and double-electron processes in collisions of Xe23+ions with helium

Abstract

We report the measurements of relative cross sections for single capture (SC), double capture (DC), single ionization (SI), double ionization (DI), and transfer ionization (TI) in collisions of Xe 23+ ions with helium atoms in the velocity range of 0.65-1.32 a.u. The relative cross sections show a weak velocity dependence. The cross-section ratio of double-(DE) to single-electron (SE) removal from He, σ DE /σ SE , is about 0.45. Single capture is the dominant reaction channel which is followed by transfer ionization, while only very small probabilities are found for pure ionization and double capture. The present experimental data are in satisfactory agreement with the estimations by the extended classical over-barrier (ECB) model.

Dynamic charge state distributions of 5 MeV Xe20+ ions penetrating through gaseous argon target

“…As shown by Ding et al [53,54], the cross section of pure ionization of target is very small near the Bohr velocity energy regime, especially for Xe-Ar collision system the single-electron removal of target (the most likely process) can be attributed to the domination of single-electron capture of projectile. Thus, we can restrict our study of Xe-Ar collision on the special case of reaction (6) with = k 1 and estimate the cross section of single-electron capture through formula (5).…”

“…With regard to electron capture, there are few scaling laws that work for the intermediate velocity (E∼25 keV/u) regime [41]. For our case, however, the electron capture of projectile could be subtly approximated by the target electron removal process, which has been discussed by Ding [53]. Selberg et al [47] have formulated a semi-empirical scaling law for the absolute cross sections of removing k electrons from the target, which can be written as:…”

Single- and double-ionization processes of antiproton-helium and antiproton–molecular hydrogen collisions in the keV energy range

“…For v p = 4.0 a.u., I c becomes positive. For I c < 0, the DI cross sections are decreased possibly because of the electron recapture effect existing in many collision processes [25][26][27][28]. For I c > 0, the shake off [29][30][31] and knock out [32][33][34] effects may contribute to the DI processes, thus enhancing their probabilities at high energies.…”