Single ionization of atomic hydrogen by proton impact as a three-body problem

Recent measurements of Schulz et al for double differential cross section of single ionization in 75 keV proton-Hydrogen collisions provide a new insight into the three-body dynamic of ion-atom collisions. We have used two different theoretical methods to calculate differential cross sections in p+H ionization as a function of the scattering angle. The first method is based on approximate solution of Faddeev-Mercuriev equations for the three-body Coulomb problem. The second method is an expansion of the transition amplitude through the second order in the projectile-target interaction. These methods have been previously used to analyze direct ionization in proton- Helium collisions. The present calculations for differential cross sections as a function of the scattering angle are in reasonable agreement with experimental data of Schulz et al. The theoretical results not only reproduce the effect of three- body dynamics at small angles, and the role of heavy particle interactions at large angles, but demonstrate the right shape of the cross section at intermediate angles.