Translational energy spectrometry of quantum-state-selected electron capture by metastable CO²⁺ ions

Abstract

Results are reported of a translational energy spectrometric study of state-selected electron-capture reactions between metastable CO²⁺ ions and H₂, He, O₂, and Kr. The experimental data are interpreted within the framework of recent ab initio calculations of the potential-energy curves of low-lying electronic states of CO²⁺. Electron capture is found to occur predominantly into moderately exoergic channels corresponding to avoided crossings of seams of potential-energy surfaces in the range of internuclear separations between 3 and 5 a.u. Some evidence is found that the CO²⁺ projectile beam may comprise not only the ¹Σ ⁺ ground electronic state but may also possess a not-insignificant long-lived excited-state (³∏ ) component.