Electron capture and excitation in low-energy collisions of He2+ with metastable 2 1S and 2 3S He -: art. no. 022707

Electron capture and excitation process in collisions of doubly charged ions of He2+ with neutral He in either a metastable S-1 or S-3 state are investigated using a theoretical model based on the adiabatic representation of the collision complex. Both ab initio and model potential calculations are used to treat the adiabatic states of the He-2(2+) molecular ion. A fully quantum mechanical treatment of the dynamics is adopted. Cross sections are calculated for energies ranging from 10(-2) to 400 eV/amu. The singlet and triplet metastable states exhibit very pronounced differences in the low eV energy range. Whereas, electron capture and excitation occur simultaneously in collisions with 2 S-1 metastable He, electron capture is dominant in collisions with 2 S-3 metastable He.