Charge transfer for proton and alpha particle colliding with helium atom at intermediate energies

Charge transfer processes for double-electron colliding systems H+ + He and He2+ + He have been studied by using the asymptotic two-state atomic expan sion method developed recently. Our results for the cross sections of elect ron capture are in good agreement with those given by the boundary-correcte d first-order Born (B1B) approximation and experimental data in high-interm ediate energies, and in the low-intermediate energies the present results a re better than those obtained by the B1B approximation. Finally, we point o ut that the reason that capture cross sections predicted by first-order per turbation theory are in poor agreement with experimental data.