Calculated absolute cross sections for the electron-impact ionization of the lanthanide atoms using the Deutsch-Märk (DM) formalism

We report results of the calculation of electron-impact ionization cross section for the lanthanide atoms Ce through Lu, which are collectively referred to as the (4f) transition-metals, using the Deutsch-Märk (DM) formalism. The lanthanides are characterized by an unfilled (5d) sub-shell and a partially filled (4f) sub-shell. The strong correlation of the open (4f) sub-shell with the (5d) sub-shell and the considerable uncertainty in the binding energies of the electrons in the (4f), (5s), (5p), (5d), and (6s) sub-shells as well as in their energetic ordering are shown to affect the choice of parameters that are required for the cross section calculations in the DM model as inferred from a comparison between the calculated DM cross sections and available experimental cross section data.