Measurements of Velocity-dependent Single- and Double-electron-capture Cross Sections for O⁷⁺ Ions Impacting He, H₂, N₂, O₂, and CH₄

Charge-exchange processes induced by highly charged ions impacting neutral materials have received considerable attention in astrophysics for decades, as they are believed to be responsible for the widespread ultraviolet and X-ray emissions observed in various astrophysical environments. In this work, with uncertainties of 8.2% in single-electron-capture (SEC) measurements, systematic measurements of single- and double-electron-capture cross sections are performed for O 7+ colliding with He, H 2 , N 2 , O 2 , and CH 4 in the energy range of 3.06–43.75 keV u −1 , filling critical gaps in the existing experimental database. Clear dependences of SEC on both collision energy and target species are observed, which is interpreted using an absorbing-sphere model.