2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/84153Scattering and reaction cross sections of $e^{\pm}-Ps$ system are calculated for total angular momentum L=0, 1 and 2 and energies between the Ps(n=2)-Ps(n=3) threshold. We solved a set of Faddeev-Merkuriev and Lippmann-Schwinger integral equations by applying the Coulomb-Sturmian separable expansion technique. We found that the excited positronium states play dominating roles in scattering processes.4 pagesAtomic Physicstext