Asymmetry of polarised electrons scattered inelastically from mercury atoms

Polarised electrons were scattered inelastically from mercury atoms at collision energies from the excitation threshold to 50 eV and at scattering angles between 30 and 120 degrees . The excitation of various target states (Hg 63P1, 63P2 and 61P1) was studied by measuring the left-right scattering asymmetry as a function of scattering angle and energy. The results show that the asymmetry is mainly caused by the combined effect of exchange and spin-orbit coupling of the target electrons, in particular at energies below 30 eV. The results are compared with numerical calculations by Bartschat and Madison (1981) (DWBA treatment) and by the Belfast Group (R-matrix treatment). The agreement is only fair, but most of the observed features are qualitatively described by the calculations.