Quantum-mechanical description of ionization, capture, and excitation in proton collisions with atomic oxygen

The basis generator method is used to propagate effective single-particle equations for ion-atom collisions to provide a mean-field description for the proton-oxygen collision system. The pure capture and ionization as well as transfer ionization cross sections are calculated using two alternative prescriptions to extract the physical information from the propagated orbitals. The sensitivity of the resonant single capture cross section to the effective single-particle potential for atomic oxygen is tested. Cross sections are calculated for 1--2000 keV proton impact and good overall agreement is found with available experiments, while some of the results are at variance with a recent model calculation. The single-particle excitation amplitudes are combined in the LS coupling scheme to obtain excitation cross sections for particular atomic oxygen configurations. The latter are compared with recent measurements for proton and electron impact. Reasonable agreement is found for many one-electron excitations and some two-electron processes.