Electron-energy and angular-distribution theory for low-energy ion-atom collisions.

We present the first {ital ab} {ital initio} calculations of electron-energy and angular distributions of saddle-point and {ital S}-promotion electrons for ionization in proton-hydrogen atom collisions. The calculations are based on outgoing wave Sturmian expansions in the frequency domain. They go beyond the usual Born-Oppenheimer separation of electron and nuclei motion and display the ``{ital v}/2`` peaks and the continuum capture cusps, missing in previous theories.