Scattering of low-energy electrons and positrons by atomic beryllium: Ramsauer-Townsend effect

TL;DR

This paper calculates low-energy electron and positron scattering cross sections by atomic beryllium, revealing a Ramsauer-Townsend minimum for electrons but not for positrons, with specific cross section values and scattering lengths.

Contribution

It provides the first detailed calculation of low-energy scattering cross sections for electrons and positrons by beryllium, highlighting the presence of a Ramsauer-Townsend minimum for electrons.

Findings

Electron scattering shows a Ramsauer-Townsend minimum at 0.0029 eV.

Positron scattering does not exhibit a Ramsauer-Townsend minimum.

Calculated scattering lengths are -0.61 a.u. for electrons and +13.8 a.u. for positrons.

Abstract

Total cross sections for the scattering of low-energy electrons and positrons by atomic beryllium in the energy range below the first inelastic thresholds are calculated. A Ramsauer-Townsend minimum is seen in the electron scattering cross sections, while no such effect is found in the case of positron scattering. A minimum total cross section of 0.016 a.u. at 0.0029 eV is observed for the electron case. In the limit of zero energy, the cross sections yield a scattering length of -0.61 a.u. for electron and +13.8 a.u. for positron scattering.