Formation of Calcium Ions by Charge Transfer

Charge transfer cross sections have been measured in the energy range from 1 to 500 eV for nine common atmospheric ions in collision with neutral calcium atoms. The ions studied are O⁺, N⁺, ${\mathrm{N}}_2^{+}$ , NO⁺, ${\mathrm{O}}_2^{+}$ , H₂O⁺, H₃O⁺, N₂O⁺, and Ca⁺. In all cases the cross sections are found to be large indicating near resonant processes. Mechanisms consistent with this observation are given. Extrapolation of the measured cross sections to thermal energies has also been carried out.