Rate constants for the reaction of SO with NO2 over the temperature range 220–960 K

Abstract

AbstractThe kinetics of the reaction of SO radicals with NO2 have been studied in a discharge flow reactor combined with an electron impact ionization quadrupole mass spectrometer at nearly 2 Torr total pressure of helium and in the temperature range 220–960 K. The reaction rate constant was determined under pseudo‐first order conditions in excess of NO2 over SO using two different methods for generation of the SO radicals: k1 = (6.7 ± 0.2) × 10−12 exp(295 ± 10)/T) cm3 molecule−1 s−1 (the uncertainties represent precision at the 2σ level, the estimated total uncertainty on the rate constant being 15% at all temperatures). The present measurements indicate that the current recommendations for k1 underestimate the rate constant at low stratospheric temperatures and overestimate it at the high temperatures characteristic of combustion.