Quantal and classical calculations of He2++Li interactions at intermediate energies. I. Charge transfer

The authors report a comparative study of the quantal and classical treatments of single-electron charge transfer from the L and K shells of Li(1s 2 2s) in collision with He 2+ ions at intermediate energies. Quantal calculations have been performed using coupled-state atomic orbital expansions with up to 43 pseudostates in the basis, within the impact parameter formalism, for impact energies of 8 to 2000 keV lab. Classical trajectory Monte Carlo calculations for L-shell capture, using a model potential for the active electron, have been performed for impact energies from 50 to 400 keV, and using an effective-charge model for K-shell capture at impact energies from 600 to 2000 keV lab.