J. Hanssen et al., INNER-SHELL CONTRIBUTION TO ELECTRON-CAPTURE IN POSITRON-ALKALI COLLISIONS, Journal of physics. B, Atomic molecular and optical physics, 31(6), 1998, pp. 1313-1319
Positronium formation through electron capture from ground state alkal
i targets is studied theoretically at intermediate and high impact ene
rgies by means of a continuum distorted-wave approximation. In this ap
proximation, distortions in the final state are introduced by using tw
o Coulomb wavefunctions associated with the positron-and electron-resi
dual target interactions. Total cross sections for lithium and potassi
um targets are computed. An estimation of the capture from the inner s
hell of lithium and potassium is given. Comparison with other theoreti
cal results and experiments is made. The contribution from the inner s
hells becomes important as the impact energy increases and seems to be
necessary to describe the measured cross sections.