Complete Break Up of Ortho Positronium (Ps)- Hydrogenic ion System
  The dynamics of the complete breakup process in an Ortho Ps - He+ system including electron loss to the continuum (ELC) is studied where both the projectile and the target get ionized. The process is essentially a four body problem and the present model takes account of the two centre effect on the electron ejected from the Ps atom which is crucial for a proper description of the ELC phenomena. The calculations are performed in the framework of Coulomb Distorted Eikonal Approximation. The exchange effect between the target and the projectile electron is taken into account in a consistent manner. The proper asymptotic 3-body boundary condition for this ionization process is also satisfied in the present model. A distinct broad ELC peak is noted in the fully differential cross sections (5DCS) for the Ps electron corroborating qualitatively the experiment for the Ps - He system. Both the dynamics of the ELC from the Ps and the ejected electron from the target He+ in the FDCS are studied using coplanar geometry. Interesting features are noted in the FDCS for both the electrons belonging to the target and the projectile. 
D. Ghosh, S. Mukhopadhyay and C. Sinha
physics.atom-ph