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 pseudostate is used to tune a semiempirical optical potential. The potential was further fine-tuned by utilizing the energy of the second lowest pseudostate. 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 a02, while Zeff achieves a value of 1310 at an energy of 0.109 eV. � 2008 The American Physical Society.
|Number of pages||13|
|Journal||Physical Review A - Atomic, Molecular, and Optical Physics|
|Publication status||Published - 2008|