Temperature and pressure dependence of the rate coefficient for the reaction NO3+ NO2+ N2→ N2O5+ N2

Abstract

A discharge flow tube experiment has been conducted to determine the rate coefficient, k₂, for reaction (2): NO₃+ NO₂+ N₂→ N₂O₅+ N₂ from 236 to 358 K and 0.5 to 8 Torr. This represents the first study of the temperature dependence of k₂ at low pressures, i.e. under conditions relevant to the middle and upper stratosphere. The date obtained here have been combined with other measurements of k₂ and the following fall-off parameters are recommended: k₀=(2.8 ± 0.4)× 10^–30(T/300)^{(–3.5 ± 0.5)} cm⁶ s^–1, k_∞=(1.66 ± 0.25)× 10^–12(T/300)^{(–0.2 ± 0.2)} cm³ s^–1, for F_c= 2.5 exp(–1950/T)+ 0.9 exp(–T/430).