Low Energy Inner-Valence Electron Impact Ionization of Argon

Abstract

We present here experimental results for the triple differential cross section (TDCS) for low energy electron impact ionization of a heavy target in the coplanar asymmetric geometry. We have investigated ionization of the 3s inner-valence orbital in argon, at an incident energy of 113. 5 eV (< 5 times the binding energy of 29. 3 eV), scattering angle of 15° and ejected electron energies of 2, 5, 7. 5 and 10 eV. The choice of target orbital and kinematics was prompted by the existence of published results of distorted-wave Born approximation calculations which predicted interesting structure in both the binary and recoil regions of the TDCS. The experimental measurements have been performed in a new low energy coincidence spectrometer. We compare our experimental results with two distorted wave Born approximation calculations. There are very large deviations between theory and experiment at all ejected electron energies investigated.