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.

*This research was supported in part by the Australian Research Council.

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