Low-Temperature Collisions of O– Anions with CH₄ and C₂H₂: Reaction Rate Coefficients and Product Branching Fractions

Using a temperature-variable cryogenic linear 22-pole radiofrequency ion trap instrument, the temperature dependency of the rate coefficient of the reaction of O– anions with CH4 has been measured at temperatures between 50 and 300 K. The temperature dependency of the rate coefficient of the reaction of O– with C2H2 has been measured at temperatures between 145 and 300 K. For both reactions, the branching fractions characterizing associative detachment and anion formation were also determined.