Improved low-energy dependence of calculated cross sections for the K-shell ionization of atoms using the Deutsch-Märk formalism

We present an improved formula to describe the energy dependence in the low-energy regime of calculated atomic K-shell ionization cross sections using the semiclassical Deutsch-Märk formalism. The modified energy dependence was obtained from a fitting procedure using recent K-shell ionization cross section data for atomic sulfur. A comparison of calculated K-shell ionization cross sections using this modified energy dependence with (1) critically evaluated experimental data for 11 other atoms and (2) cross section shapes derived from other predictive formulae revealed good agreement, not only in the low-energy regime, but also at relativistic impact energies.