Reactions of N₄⁺ with O₂, CO₂, H₂, and D₂ and mobilities of N₄⁺ in nitrogen

The rate constants for the reaction of N₄⁺ with O₂, CO₂, H₂, and D₂ have been studied as a function of mean relative kinetic energy in a flow-drift tube using a nitrogen buffer gas. The N₂⁺/N₄⁺ equilibrium, which would otherwise deleteriously effect such a study, was suppressed by adding a trace of H₂ as a purge gas that preferentially reacted with N₂⁺. The reaction rates of N ₄⁺ with CO₂ and O₂ are found to be fast and independent of energy from 0.04 to 0.16 eV. The reactions of N ₄⁺ with H₂ and D₂, however, have very small rates at room temperature, but the rates increase dramatically with increasing energy, an effect that is attributed to a sensitivity of the reactions to N₄⁺⁺ vibrational excitation. The reaction of N₄⁺ with H₂ was studied as a function of temperature and an activation energy obtained. The mobility of N₄⁺ in N₂ was extended to higher E/N values than could be done in earlier studies since the effects of the N ₂⁺/N₄⁺ equilibrium were suppressed in the present investigation.