Integrated oscillator strengths for multi-ionization processes under the Bethe-Born formulation

This work presents an empirical expression that allows one to estimate the integrated oscillator strength for multi-ionization of an atomic target reaction by electron impact as a function of the target final charge state. The individual ionization process is considered as a transition into the continuum and described through the Bethe formula. The results are compared with data for noble gases available in the literature.