State-selective differential single-electron-capture cross sections forO2+-He collisions

Energy-gain spectra for single-electron capture by ${\mathrm{O}}^{2+}$ ions colliding with He have been measured at laboratory energies between 60 and 200 eV, and scattering angles between 0° and 4°. The spectra indicate that the predominant exit channel is the (2$p^3$ ${\mathrm{}}^2$P) excited state of ${\mathrm{O}}^{+}$. Differential cross sections for capture into the ${(}^2$P) state were also measured. The data show an oscillatory structure. The measurements are in qualitative agreement with recent theoretical calculations based on a full quantum-mechanical description.