State-selective Differential Cross Section Measurements for the One-electron Capture Process in O 2+ –He and N 2+ –He Systems at E lab = 48 eV

Performing high-angular-resolution measurements, we studied the relative state-selective differential cross sections (DCSs) for the following reaction channels: O2+ (2s22p2 3P) + He (1s2 1S) → O+ (2s22p3 2P) + He+ (1s 2S) + 5.52 eV and N2+ (2s22p 2P) + He (1s2 1S) → N+ (2s22p2 3P) + He+ (1s 2S) + 5.01 eV. The collision energy in the laboratory frame, Elab, was 48 eV. We applied a two-state semiclassical analysis based on ab initio potentials for the OHe2+ and NHe2+ systems. We concluded that the rainbow scattering and Stückelberg oscillations characterize the observed DCS structure in the O2+–He case. In contrast, in the N2+–He case, the prominent peak of the DCS at an angle of 0° is due to the forward glory scattering. Rainbow structures are also seen. The measured DCS was deduced to appear as the envelope of rapid oscillations in the theoretically calculated DCS.