Systematic study of charge-state and energy dependences of transfer-ionization to single-electron-capture ratios forFq+ions incident on He

Abstract

This paper presents an investigation of the charge-state and energy dependences of transfer-ionization ͑TI͒ and single-electron-capture ͑SC͒ processes for fluorine ions ͑q =4+ to 9+͒ incident on a supersonic He jet target. The measurements were made for beam energies between 0.5 and 2.5 MeV/ u. A recoil ion momentum spectrometer was used to separate TI and SC based on the longitudinal momentum transfer and time of flight of the recoil ions. The cross-section ratios for TI to SC, R = TI / SC , were determined and observed to decrease monotonically with velocity. The values of R were combined with measured total transfer cross sections to deduce the cross sections for both SC and TI. Coupled-channel calculations of the energy dependence of TI and SC for F 9+ + He were compared to the experimental cross sections as well as the values of R. The calculated cross sections were found to be slightly lower and the R values slightly higher than the measured values, but with approximately the same energy dependences. A q 2 scaling of the He 2+ + He data was also compared to the present data and was found to give unexpected good agreement.

Charge and Energy Dependences of Ionization and Transfer for Helium in Collisions with Fast Charged Projectiles

“…5 for the A 8+ -He collisions and in Fig. 6 for the A 9+ -He system, respectively, in the energy range from 0.5 to 3 MeV/𝑢, together with the results measured by Ünal et al [5] The calculations are in general agreement with the experimental results. It is seen that the cross sections show a steep decrease with the projectile energy, to which two important reasons can contribute: firstly, the capture distance 𝑅 𝑐 is in inverse proportion to 𝑣 2 𝑝 , that is, the capture distance will decrease rapidly as the projectile energy increases; secondly, with increasing projectile velocity, the lack of interaction time between projectiles and target electrons is the other reason.…”

Relative cross-sections of charge transfer and ionization processes between multiply-charged ions and He at low and intermediate energies

“…It is well known that helium is the simplest target atom on studying the double-electron processes. In the past, a number of relevant experiments [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16] were performed, which included the measurements by our group [1,8,9,11] for C q+ , O q+ and F q+ + He collisions at low to intermediate velocities. In general, the processes in collisions of projectiles A q+ with He can be described by the following reactions: single ionization (SI) : A q+ + He → A q+ + He + + e − (i) double ionization (DI) :…”

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

“…), ionization is the dominant process. In the two velocity ranges mentioned above, the reaction channels are relatively homogeneous and a number of measurements [6][7][8][9][10][11] have been carried out in collisions of HCI's with helium atoms. However, in the overlap region (v p ∼ 1 a.u.…”