The effect of target fine-structure on the measured spin asymmetries for the electron-impact ionization of Ar(2p)

Here we present spin- and fine-structure resolved results for the inner-shell ionization of argon. Measurements were performed using an incident beam of spin-polarized electrons and a highly-efficient multi-parameter electron spectrometer. The experimental results are compared with fully-relativistic distorted wave Born approximation (DWBA) calculations in two variants, one using potentials generated with density functional theory (DFT) and the second using a high-quality Dirac-Fock (DF) wave function. Differences between the two calculations are discussed, with both found to be in reasonable agreement with experimental spin-asymmetry and branching-ratio measurements. Both measurement and calculation were performed under kinematical conditions where the contribution from the exchange between the scattered electrons and the electrons in the residual ion is small, highlighting the effect of target fine-structure on the measured spin asymmetry and derived branching ratios.