Coupled-state calculations for excitation, charge transfer, and ionization in 1-75-keV proton-hydrogen-atom collisions

Coupled-state calculations based upon a two-center expansion in atomic orbitals and pseudostates have been performed for ${\mathrm{H}}^{+}$+H in the 1-75-keV region. Cross sections for excitation and charge transfer to $n=2\mathrm{}$ states as well as total ionization cross sections are reported. It is shown that the calculated cross sections are not sensitive to the specific set of pseudostates included if the low-energy continuum states are reasonably well represented. The present results compare favorably with several sets of experimental data and with some large-scale calculations. The need for further experimental data in some areas is discussed.