A new scaling law for ionization.

A new scaling law for ionization is presented. Our new model scales the cross sections by Z^4/3 and the impact energies by Z^2/3, rather than by Z in both cases as suggested by Olson et al. Using available CDW-EIS calculations and experimental data for ionization of helium by fully stripped ions, it is shown that this "modified Z" scaling yields a universal curve throughout the entire energy regime, not just for the region above the cross section maximum. Similar results are obtained for ionization of molecular hydrogen. [ABSTRACT FROM AUTHOR]