Cross Section Invertion Between Double Electron Capture And Transfer Ionisation In Low Energy Highly Charged Ion-He Collisions

Ion-atom collisions have been an active and important field in atomic physics. Highly charged ions-atom collisions involve the mechanics of many-body collisions and the interactions of ion-atom,ion-electron,and electron-electron.Early experiments deal with single electron process which are well understood by both experiments and theories at present. But the experiments only determined the final charge states of projectiles without analyzing the charge states of the recoils, so these methods could not distinguish the single electron capture(SC) processes from transfer ionization(T1) processes which both charge transfer process in collisions of multi-charged ions with neutral atoms and molecules is of great importance not only in basic atomic physics but also in applied fields such as fusion plasmas and astrophysics.The cross-sections ratios of double electron capture and transfer ionization of helium target induced by Aq+(q=4,5,6,7) ions were measured by means of the position sensitive detector and time-of-flight techniques. A potential parameter (Ω) based on Statistical Interpretation model was defined. It is found that there is a cross point for the cross-section ratios curve of double electron capture and transfer ionization atΩ=1.0, and forΩ<1.0 the double electron capture is key reaction channel of double electron transfer of helium process, forΩ≥1.0 the transfer ionization is key reaction channel. The cross section invertion between double electron capture and transfer ionisation is also found in collisions between Arq+(q=4,5,6,7,8) ions and Ar atoms.