Left-right asymmetry for scattering of polarized electrons from thallium and lead atoms

Abstract

Polarized electrons were scattered elastically and inelastically from unpolarized thallium and lead atoms. The left-right scattering asymmetry has been measured for energies ranging from 2.5 to 14 eV at scattering angles between 35' and 125'. The influence of the electronic configuration of the valence electrons on the results of the asymmetry function is discussed. For elastic collisions no clear-cut conclusions about the significance of the 'fine-structure' effect compared with the Mott scattering effect can be drawn. Numerical results from R-matrix calculations show good agreement with the experimental data for thallium, whereas the theoretical predictions for lead are less satisfactory.

Close-coupling calculations for low-energy elastic electron scattering from thallium atoms

“…Accidentally, the most primitive one-state calculation (Fig. 1) gives very good agreement with the experimental data of the Mfinster group [5,6], provided the spin-orbit interaction is scaled with the effective nuclear charge Zef r obtained from the reproduction of the fine-structure splitting in the target spectrum. On the other hand, the three-state and seven-state expansions with the same representation of the spin-orbit interaction deviate significantly from the experimental data, with the "best" model (the seven-state calculation) clearly yielding the worst results.…”

“…This is due to the additional dipole allowed transitions from the ground state to the (7s)281/2 and the (6d) 2D3/2 states, respectively. Figures 1-3 show the results for the asymmetry function S A for elastic electron scattering from thallium atoms in "6 ,2pO their ground state t P) ~/e, at incident energies of 1.0, [5] (for 3.0 eV) and of Diimmler et al [6]. Also shown are fullrelativistic "general density functional" calculations by Fritsche et al…”

“…This is followed by numerical results for elastic scattering at a few selected energies. These results are compared with recent experimental data of the Mfinster group [5,6] as well as those from a fullrelativistic calculation based on the "generalized density Ihnctional" (GDF) theory [7,8]. Finally, some conclusions are drawn in Sect.…”

Relativistic B-Spline R-Matrix Calculations for Electron Scattering from Thallium Atoms

“…It has an open-shell 6s 2 6p with nonvanishing orbital angular momentum as its ground-state configuration. Benchmark experimental data for e-Tl collisions at low energies were produced by the Münster group [5][6][7]. Kaussen et al [5] investigated the spin polarization in elastic scattering of unpolarized electrons from several heavy atoms, including thallium, for selected incident-electron energies between 6 and 180 eV.…”

“…Kaussen et al [5] investigated the spin polarization in elastic scattering of unpolarized electrons from several heavy atoms, including thallium, for selected incident-electron energies between 6 and 180 eV. Geesmann et al [6] used a source of spin-polarized electrons, which were scattered elastically and inelastically from an ensemble of unpolarized thallium atoms, to study the spin asymmetry function for incident energies ranging from 3 to 14 eV and scattering angles in the range of 35 • to 125 • . Later, the measurements were extended to energies below 2 eV by Dümmler et al [7].…”