Positron-atom scattering using pseudo-state energy shifts
Abstract
A method 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 after an initial validation on the e+ - Cu system. The energy shift between a small reference calculation and the largest possible configuration interaction calculation of the lowest energy pseudo-state is used to tune a semi-empirical optical potential. The potential was further fine-tuned by utilizing the energy of the second lowest pseudo-state. The s- and p-wave phase shifts for positron scattering from Mg and Zn are given from threshold to the first excitation threshold. The e+ - Mg cross section has a prominent p-wave shape resonance at an energy of about 0.096 eV with a width of 0.106 eV. The peak cross section for e+ - Mg scattering is about 4800 a_0^2 while Z_eff achieves a value of 1310 at an energy of 0.109 eV.
Cite
@article{arxiv.0802.1371,
title = {Positron-atom scattering using pseudo-state energy shifts},
author = {J. Mitroy and J. Y. Zhang and M. W. J. Bromley and S. I. Young},
journal= {arXiv preprint arXiv:0802.1371},
year = {2009}
}
Comments
15 pages, 15 figures, submitted to PRA (updated following referee comments)