Positron elastic scattering by a semifilled-shell atom

TL;DR

This paper presents a theoretical study of positron elastic scattering by a semifilled-shell atom, highlighting the roles of electron correlation and virtual positronium formation, with a focus on manganese as a case study.

Contribution

It introduces a new theoretical framework accounting for both electron correlation and virtual positronium formation in positron scattering by semifilled-shell atoms.

Findings

Electron correlation significantly affects scattering outcomes.

Virtual positronium formation alters energy states and scattering behavior.

Distinct differences between electron and positron scattering processes are demonstrated.

Abstract

We theoretically study the positron elastic scattering by an atom with a multielectron semifilled subshell in its structure. The positron scattering by the Mn($...3d^{5}4s^{2}$,$^{6}S)$ atom with a $3d^{5}$ semifilled subshell ($e^{+}+Mn$ scattering) is chosen as a case study. We account for both the electron correlation and the formation of a $e^{+}+e^{-}$ virtual positronium (Ps) in the intermediate states of the $e^{+}+Mn$ system. Electron correlation is taken into account in the framework of the self-energy part of the scattering positron Green function generalized for the application to semifilled-shell atoms. The influence of the virtual Ps formation on $e^{+}+Mn$ scattering is taken into account by the reduction of the energy of the virtual \textit{positron plus atomic-excited-configuration} states by the Ps-binding energy, to a reasonable approximation. We unravel the importance and specificity of the influence of both the virtual Ps and electron correlation on $e^{+}+Mn$ elastic scattering. We demonstrate spectacular differences between the electron and positron scattering processes.