Analytic cross sections for charge transfer of H+, H- and H with atoms and molecules

Analytic formulas have been developed to express six types of total cross sections for charge transfer in collisions of H+, H- and H with gaseous atoms and molecules in the energy region from about 50 to 5 x 106 eV. The functional form of the formulas is a generalization of the one used by Green and McNeal to express the cross section for single-electron capture of H+. Values of adjustable parameters in the formulas have been determined by the least-squares fit to available experimental data. The rms deviation of the data from the formula is about 20% for each type of cross sections except when large discrepancies exist among the data. (author)