Superoxide anion (O$_{2}\negthinspace^{-}$) collisions with CO$_{2}$ molecules in the energy range 50-950 eV

Abstract

A novel gas-phase molecular scattering study is reported for O$_{2}\negthinspace^{-}$ colliding with CO$_{2}$ for impact energies ranging from 50 to 950 eV. The absolute total electron detachment, relative total and partial ionization cross sections have been measured within this energy range and the positive ion yield of those produced during the collisions has been obtained. The primary anionic beam projectile is produced in a pulsed hollow cathode discharge induced plasma, and its interactions with the neutral molecular target occur in a gas cell at a well-known constant pressure. For impact energies above 500 eV high mass (m $>$ 44 u) charged complexes have been detected. With the aid of a theoretical study, using ab initio methods, we propose a mechanism to infer on the formation of these cationic species, which have been assigned as projectile-target stable compounds (CO$_{3}\negthinspace^{+}$ and CO$_{4}\negthinspace^{+}$).