Extension of the DM formalism for the calculation of cross sections for the multiple ionization of atoms to the formation of highly charged ions

This paper extends the semi-classical Deutsch-Mark (DM) formalism, which has been applied previously to the formation of multiply charged ions A(m+) (m = 1-5) by electron impact on the neutral atoms, to the formation of highly charged ions (m > 5). This is accomplished by introducing a modified fitting procedure to determine the empirical weighting factors, which are characteristic of the DM formalism, for the formation of highly charged ions. Our calculations are compared with available experimental results and with the predictions of other semi-empirical methods. (C) 1997 Elsevier Science B.V.