Formation of the positronium negative ion in collisions of positronium with atomic hydrogen and helium

Abstract
The distorted-wave Born approximation and a CTMC model are employed to provide theoretical estimates of the cross sections for the formation of the positronium negative ion (Ps-) in collisions between positronium (Ps) and atomic hydrogen or helium, in the energy range 27 to 170 eV. In the calculation, a previously developed one-electron approach is employed to describe the Ps- ion, and a similar model is also used to describe helium targets.