2-ELECTRON CAPTURE FROM HELIUM-LIKE ATOMIC SYSTEMS BY COMPLETELY STRIPPED PROJECTILES

Asymmetric and/or symmetric double-charge exchange in fast collisions of bare nuclei with helium-like atomic systems is considered. We emphasize the need for going beyond the standard independent particle model and consequently employ the four-body version of the boundary corrected first Born (CB1) approximation with a full account of the long-range Coulomb effects arising from the relative motion of the scattering aggregates. A method is devised which is capable of reducing the transition amplitudes T(if)((CB1)+/-) to two-dimensional real integrals. As a test of the proposed theory, we currently investigate the double-electron capture from helium by completely stripped lithium. The prior and post total cross sections obtained are found to be in satisfactory agreement with the available experimental data at impact energies ranging from 250 to 2000 keV.