Studies of charge exchange in symmetric ion-ion collisions

Abstract

We have measured the total cross sections for single charge exchange in He 2+-He + , Ne 2+-Ne + and Ar 2+-Ar + collisions at centre-of-mass energies of 1.8-14.8, 1.8-10.8 and 2.8-7.3 keV, respectively, using an intersecting beam technique. The results for He 2+-He + collisions are compared with existing measurements and calculations. For Ne 2+-Ne + and Ar 2+-Ar + the measured cross sections are compared with results from new close-coupling calculations based on a one-electron model potential description of the collision system.

Charge transfer in collisions of H2+ions with He2+and Ar2+

“…The resonant reactions He + +He 2+ → He 2+ +He + and Ar + +Ar 2+ → Ar 2+ +Ar + have been used to set up the electrostatic analysers and verify the cross section measurement. The cross sections obtained from equation (3) however are smaller by a factor 1.74 ± 0.2 and 1.72 ± 0.2 respectively than those measured by Melchert et al [16] and Chen et al [3], which agree very well with theory. We attribute this discrepancy to an efficiency loss due to the aperture of the hemispherical analyser for the slow beam.…”

“…Charge changing collisions between ions are of fundamental interest as an ideal testing ground for theory [1][2][3][4] as well as for their application in plasma physics, accelerator and fusion research [5]. In contrast to ion-atom collisions, however, the study of ion-ion collisions is still in its infancy and, furthermore, most studies focused on collisions between atomic ions.…”

“…The calculation shows that the electron is predominantly captured into He + (n = 2). In reaction (2), a model potential was used to describe the Ar 2+ projectile [3] and only capture into Ar + (3p) was assumed. These atomiccapture amplitudes were then added coherently, according to equation ( 5), for two scattering centres at a distance of ρ = 2 au.…”

Roadmap on photonic, electronic and atomic collision physics: III. Heavy particles: with zero to relativistic speeds

“…Whereas ion-ion experiments for high-energy physics (like the experiments at CERN) are currently carried out, ionion collisions for atomic physics have been so far performed mainly in the context of magnetically confined plasmas [108]. There, in the low velocity regime, typically at center-of-mass energies of a few keV up to a few 100 keV, cross section measurements of the charge transfer process [109,110] (by far the dominant process) were performed with light ions (up to oxygen) for collisions with bare, hydrogen-or helium-like ions, or with low-charged ions for the heavy systems like Bi and Pb, where charge states of up to 4+have been used.…”

Charge transfer in homonuclear collisions of heavy ions

“…Charge-changing collisions between multiply charged ions are not only of fundamental interest as an ideal testing ground for theory [1][2][3][4]. Data on these processes, especially in homonuclear collision systems, are also needed in plasma physics as well as in fusion and accelerator research.…”