Robust Estimates of Hydrogen-Impact Ionization Cross Sections Over a Wide Energy Range

We describe a simple and effective procedure to estimate hydrogen-impact ionization cross sections over the energy range of tens of keV/nucleon to tens of MeV/nucleon. The procedure is valid in the first Born approximation using known or estimated electron-impact cross sections. The original Bates-Griffing relation between the two sets of cross sections is reformulated and a correction factor due to multiple transitions is introduced. Sample calculated ionization cross sections for helium and carbon collisions with hydrogen are presented