Some additional information on the dynamics of the reaction O+2+CH4

The reaction O+2+CH4 was studied in a selected-ion drift tube in a He buffer at various temperatures. At sufficiently high buffer pressure the reaction product O+2 ⋅ CH4 was observed beside the well known third order kinetics. From a study of the reaction equilibrium O+2 ⋅ O2+CH4 ⋅ O+2 ⋅ CH4+O2 the bond energy of O+2 ⋅ CH4 was determined. Values of ΔH=−37.7(±1.5) kJ/mol and ΔS=−42(±15) J/mol ⋅ K were found for the association of O+2 and CH4. These values are very close to those for the O+2–O2 bond.