Positron elastic scattering by a semifilled-shell atom

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.

9 pages, 8 figures

References in corpus (5)

• Positron scattering and annihilation on noble gas atoms
• Recent progress in the description of positron scattering from atoms using the Convergent Close-Coupling Theory
• Detection of positron-atom bound states through resonant annihilation
• Attosecond time delay in the photoionization of Mn in the region of the $3p\to 3d$ giant resonance
• Electron elastic scattering off a spin-polarized Cr atom