Kinetics of the self reaction of CF3O2 radicals and their reaction with O3 at 298 K

Abstract

Two low-pressure discharge-flow systems, one equipped with laser-induced fluorescence (LIF) detection of NO ₂ and the other mass spectrometric detection of NO ₂ , have been employed to determine the rate constant for the self reaction CF ₃ O ₂ +CF ₃ O ₂ →products, at T=298 K and P=13 Torr. The phenomenological rate constant is k ₁ =(2.0±0.1)×10 ^-12 cm ³ molecule ^-1 s ^-1 ; however, after consideration of secondary chemistry, numerical modelling suggests that the true rate constant is k ₁ =(1.2±0.3)×10 ^-12 cm ³ molecule ^-1 s ^-1 . In addition, an upper limit has been derived for the reaction CF ₃ O ₂ +O ₃ →products of k ₃ <3×10 ^-14 cm ³ molecule ^-1 s ^-1 . The mechanism of the self reaction and the atmospheric implications of these results are discussed briefly.