Electron Capture and Loss in Collisions of Heavy Ions with Atomic Oxygen

Electron-capture and electron-loss cross sections for various gaseous (N⁺, O⁺, Ar⁺, Kr⁺, and Xe⁺) and metallic (Al⁺, K⁺, Fe⁺, Ba⁺, and Ba⁺⁺) ions in collisions with atomic oxygen have been measured in the energy range 30 keV to 2 MeV. Beam-in-static-gas techniques were employed. Ions formed by an electron-impact ion source were mass selected by a rf quadrupole mass filter and were accelerated by a Van de Graaff accelerator into a fast well-collimated ion beam. This ion beam was then steered through an atomic-oxygen target chamber development to provide a collision region containing thermally dissociated oxygen atoms in the ground state. The charge states of the emerging fast-ion beam were measured and this information along with knowledge of the atomic-oxygen-target thickness within the target chamber was used to deduce the electron-capture and electron-loss cross sections of the particular fast heavy ion on neutral atomic oxygen. Comparison with theoretical calculations and other experimental data were made where possible.