Positron-atom scattering using pseudo-state energy shifts

POSTER

Abstract

A simple way to generate low-energy phase shifts for elastic scattering using bound-state calculations is applied to the problem of $e^+$-Mg and $e^+$-Zn scattering. The method uses the energy shift between a small reference calculation and the largest possible configuration interaction calculation of the lowest energy pseudo-state/s as the input to tune a semi-empirical optical potential. The $s$- and $p$-wave phase shifts up to the first excitation threshold are given for both systems. The $e^+$-Mg cross section has a prominent $p$-wave shape resonance at an energy of about 0.0094 eV with a width of 0.0108 eV. The cross section maxima is about 4800 $a_0^3$, while the $Z_{\rm eff}$ achieves a value of 1300 at an energy of 0.108 eV.

Authors

  • Jim Mitroy

    ARC Center for Anti-Matter Studies, School of Engineering, Charles Darwin University, Darwin N.T., Australia, Charles Darwin University, Faculty of Technology, Charles Darwin University, Darwin NT 0909, Australia, School of Engineering, Charles Darwin University, Darwin, NT, Australia

  • Jun-Yi Zhang

    ARC Center for Anti-Matter Studies, School of Engineering, Charles Darwin University, Darwin N.T., Australia, Faculty of Technology, Charles Darwin University, Darwin NT 0909, Australia

  • Michael Bromley

    Department of Physics, San Diego State University, San Diego CA, Department of Physics and Computational Science Research Center, San Diego State University, San Diego CA, Department of Physics, San Diego State University, San Diego, CA

  • Scott Young

    Department of Physics, San Diego State University, San Diego CA