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

摘要

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(0)(2) 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(0) for electron and +13.8 a(0) for positron scattering.