Charge transfer between C²⁺ and H₂, N₂, He, and CO at electron-volt energies

We measured the total charge-transfer rate coefficients for C²⁺ with H₂, N₂, and CO using a cylindrical radiofrequency ion trap. C²⁺ ions were produced by the electron impact of residual CO in an ultrahigh-vacuum chamber. The rate coefficients for C²⁺ with H₂, N₂, and CO are measured to be 8.77 (0.71)×10^-11 cm³ s^-1 (T_equiv=2.63×10³ K), 1.08 (0.07)×10^-10 cm³ s^-1 (T_equiv=1.17×10⁴ K), and 4.58 (0.29)×10^-10 cm³s^-1 (T_equiv=1.17×10⁴ K). The rate coefficient for C²⁺ with He is estimated to be less than 10^-12 cm³s^-1 (T_equiv=4.38×10³ K).