Charge-transfer excitation in collisions of He+ ions with CO2 molecules under beam conditions

The charge-transfer excitation of CO 2 + in the collisions of He+ ions with CO2 was investigated in the (5/1000) eV laboratory energy range of the He+ projectile. The observed luminescence is due mostly to the electronically excited CO 2 + (A, B) molecules. The cross-section for the reactions leading to the CO 2 + (A + B) products varies only slightly in the (200/1000) eV laboratory energy range. The observed decrease of the excitation function for energies up to ∼200 eV is probably associated with the formation of long-lived collision complex. A normalization procedure has been used to obtain the absolute emission cross sections for the charge transfer excitation processes studied.