Kinetic study of the Na + O2+ He reaction in the temperature range 392–777 K

Abstract

A kinetic study of the reaction Na + O₂+ He [graphic omitted] NaO₂+ He has been carried out in a fast-flow reactor in the temperature and pressure ranges of, respectively, 392–777 K and 4–14 Torr. Sodium atoms are generated either by thermal evaporation of sodium metal or by the technique of microwave-induced plasma afterglow atomization. Atomic absorption spectroscopy is used as the detection technique for atomic sodium. A fit of k₂ to the expression A(T/300)ⁿ yields k₂=(8.6 ± 0.7)× 10^–31(T/300)^{–1.04 ± 0.16} cm⁶ molecule^–2 s^–1. This rate expression will be compared with kinetic data derived for the above reaction on the basis of time-resolved flash photolysis and excimer laser photolysis measurements. Using the Troe formalism, values of k₂ are calculated in the temperature range 200–2000 K and the importance of the reaction in the burnt-gas region of oxygen-rich flames is discussed.