A semiclassical method for the calculation of cross sections for multiple ionization of atoms by electron impact

The semiclassical Deutsch-Märk (DM) formalism for the calculation of absolute cross sections for the single ionization of atoms has been extended to the calculation of cross sections for the multiple ionization of ground state atoms X + e^- → X^m+ + (m + 1)e^- (degree of ionization m > 3). Comparisons are presented with the predictions of two recently published semi-empirical methods and with available experimental data for some selected targets. The DM formalism is conceptually straightforward to apply; the semi-empirically determined parameters can easily be related to physical quantities and the formalism has already been successfully applied to the single ionization of atoms, ions, molecules, radicals and clusters, as well as to the double and triple ionization of atoms. In those cases where predictions from all three methods and experimental data are available, we find that, with very few exceptions, our method yields a level of agreement with the experimental data which is comparable to or better than the predictions from the other two methods.