Absolute cross sections for electron loss, electron capture, and multiple ionization in collisions of Li²⁺with argon

Abstract

Exclusive absolute cross sections for the electron loss and capture processes, accompanied by target multiple ionization and pure target multiple ionization, as well as total electron loss and capture cross sections, in collisions of Li 2+ with Ar have been measured in the 0.5-3.5 MeV energy range. The experimental data of the total electron loss cross section are compared with theoretical results based on the plane-wave Born approximation and the free-collision model, and with the available experimental data. Some discrepancies are observed when comparing the experimental data with the theoretical models, which can be attributed to the competitive mechanisms that lead to electron loss. The dependences of the single-capture and transfer-ionization processes on the projectile charge state are similar to those observed for collisions between other low-charged light ions and noble-gas targets. The same behaviour is observed when one compares the present data for the single-and double-ionization cross sections with those for He 2+ projectiles on Ar. These facts indicate that the dynamics of the collision does not seem to depend on the projectile species, so that few-electron projectiles may act as structureless point charges in the intermediate-to high-velocity regime.

A Time-Dependent-Density-Functional-Theory Study of Charge Transfer Processes of Li2+ Colliding with Ar in the MeV Region

“…On the whole, both single-charge transfer (SCT) and double-charge transfer (DCT) cross sections decrease monotonously with the increase of the impact energy. Regarding SCT cross sections, our results agree well with the experimental data [37,38] from 0.5 to 1.0 MeV. For the region of 1.5-2.5 MeV, while the present results underestimate the experimental data roughly 20% ∼ 50%, they still give the right tend.…”

“…Our results (stars and circles) are calculated by choosing the 𝑉 T to be the whole computational box. The other scattered symbols are the experimental data of Losqui et al in Ref [37]. and Dmitriev et al in Ref [38]…”

Multiple ionization of argon by helium ions

“…We also include in figure 2 the recent measurements of multiple ionization cross sections of Ar by Li 2+ by Sigaud and coworkers [23]. As already noted in [23], He 2+ and Li 2+ values are approximately the same, within the experimental uncertainties.…”

“…Different experimental measurements were carried out for the He-Ar system [17][18][19][20][21][22], with coincident measurement of projectile and target final charge state in order to have separate data of pure ionization (the target electron in the continuum, the ion charge unchanged) and electron transfer (the electron bound to the projectile). Also of interest are the measurements on multiple ionization of Ar by + Li 2 ions by Sigaud and coworkers [23], which also add to the framework of present calculations.…”

Multiple ionization of Ar by alpha particles

“…Different experimental measurements involve the He-Ar system, i.e [1][2]. Also of interest are the very recent measurements on multiple ionization of Ar by Li +2 ions by the Rio de Janeiro group [3]. Our goal is to analyze the +2 charge projectiles in view of previous double ionization results by proton impact, which show an overestimation at high energies (postcollisional region).…”