Double- and Single-Charge Transfer in Collision of C6+Ion with He Atom at Low Impact Energies

Abstract

Total double- and single-charge transfer cross sections are calculated for the collisions of C 6+ ion with He atom in the impact energy region 0.1≤ E ≤10 keV/amu. The perturbed-stationary-state method in the impact parameter approximation is used with a basis set of SCF-CI molecular orbitals. There are many curve crossings among the adiabatic potential curves. A diabatic treatment is, however, found to be useful for the most of curve crossings. The single-charge transfer mainly occurs through the avoided crossing near 5 au, while the double-charge transfer takes place via a two-step one-electron transfer or a direct process. Hence the double-charge transfer cross section obtained(∼10 -16 cm 2 ) is about a tenth of the single-charge transfer cross section in these impact energies.