Ionization and excitation in collisions between antiprotons and hydrogen atoms

Coupled-state cross sections have been determined for ionization and excitation in intermediate (keV)- energy collisions between antiprotons and hydrogen atoms using some of the same double-center Sturmian bases as were recently used for proton projectiles\footnote{T. G. Winter, Phys. Rev. A {\bf 80}, 032701 (2009).}. The use of a double-center basis for antiproton projectiles, in spite of there being no capture channels, was suggested and carried out by Toshima with a large Gaussian basis\footnote{N. Toshima, Phys. Rev. A {\bf 64}, 024701 (2001).}. The present results for ionization will be compared with the double-center results of Toshima and the single-center results of Igarashi \textit{et al.}\footnote{A. Igarashi, S. Nakazaki, and A. Ohsaki, Phys. Rev. A. {\bf 61}, 062712 (2000).} and McGovern \textit{et al.}\footnote{M. McGovern, D. Assafr\~{a}o, J. R. Mohallem, C. T. Whelan, and H. R. J. Walters, Phys. Rev. A {\bf 79}, 042707 (2009).}, and the crosssections for excitation of individual states up to $3d$ will be compared to the numerical results of Sakimoto \footnote{K. Sakimoto, J. Phys. B {\bf 33}, 5165 (2000).}.