Charge and energy-dependence of the Gaussian description of the triply differential cross sections for equal-energy sharing photo-double-ionization of two-electrons ions

Abstract

We evaluate triply differential cross sections (TDCSs) for the photo-double-ionization (PDI) of He-like ions, and equal electron energy sharing, by using the SC3 model for the three-body final state. These cross sections are fitted with the usual dipolar Gaussian form which is found able to describe the theoretical TDCS, and could be applied for the interpretation of experimental data even at intermediate photon energies. We determine the dependence of the correlation factor on the excess energy $({E}_{f})$ and target nuclear charge $(Z)$. We find that its width has an ${E}_{f}^{1∕4}$ dependence near the atomic double-ionization threshold but departs from this law and attains a plateau as the excess energy increases. We compare our results with the predictions of classical and semiclassical Wannier approaches.