Differential cross sections for elastic electron scattering by ytterbium atoms in the energy range 2–2000 eV: I. Real optical potential part approximation

Abstract

Elastic electron scattering by ytterbium atom was studied within the 2 eV–2 keV interaction energy range using an approximation of parameter-free real part of the optical potential (OP) with allowance for spin–orbit interaction. The analytical approximation parameters were obtained for the static potential (being the main OP term), and the electron density of the target atom was calculated within the local approximation of relativistic density functional theory. The exchange potential was taken in the free electron gas approximation. The parameter-free correlation-polarization potential was used to take into account the polarization of the atom by the incident electron. Integral, momentum transfer and viscosity cross sections as well as angular dependences of differential elastic scattering cross sections (DCSs) were calculated. The positions of nine critical DCS minima were determined, the highest-energy minimum being located at [1150.9 eV; 135.70°]. A good agreement of the angular dependence of DCS with the experimental data available for 10, 20, 40, 60 and 80 eV was obtained. The above cross sections were also compared with other theoretical data, namely with the relativistic Dirac–Fock calculations with no absorption being taken into account. The phase analysis performed using the variable phase method has shown the differences in the available theoretical calculations of DCS at 10 eV to be caused principally by the manner of the exchange interaction being taken into account.