Cross sections for electron detachment of the hydrogen negative ion and for single ionization of helium by antiproton impact

We have used the one-center close coupling method to calculate the electron detachment cross sections of the hydrogen negative ion by antiproton impact. The one- and two-electron treatments give similar cross sections for single detachment. The double-detachment cross section is estimated within an independent particle model, and is at most a few percent of the single-detachment cross section. The single-ionization cross sections of helium in antiproton impact are recalculated including the double-ionization channels which were completely neglected in our previous calculation [Phys. Rev. A 62, 052722 (2000)]. However, the inclusion of the double-ionization channels does not make a great difference for the single-ionization cross sections above 1 keV and disagreement still remains with the data measured by Hvelplund et al. [J. Phys. B 27, 925 (1994)].