The kinetics of the high-temperature reactions of CF 3 radicals with O( 3 P) and H atoms has been investigated experimentally and theoretically. The product channels of the CF 3 + O( 3 P) and CF 3 + H reactions were examined by calculating their branching fractions with the multichannel Rice-Ramsperger-Kassel-Marcus (RRKM) theory. Structural parameters, vibrational frequencies, and threshold energy required for the RRKM calculation were obtained from an ab initio MO calculation. The theoretical calculation showed that the productions of CF 2 O + F and CF 2 ( 1 A 1 ) + HF were the unique possible channels for the CF 3 + O( 3 P) and CF 3 + H reactions, respectively, and that the other channels such as deactivation were negligible for both the reactions. The rate coefficients for these reactions were experimentally determined by using a shock tubeatomic resonance absorption spectroscopy technique over the temperature ranges of 1900-2330 and 1150-1380 K and the total density ranges of 8.2 × 10 18 -1.2 × 10 19 and 6.1 × 10 18 -9.8 × 10 18 molecules‚cm -3 . Nitrous oxide and ethyl iodide were used as precursors of electronically ground-state oxygen and hydrogen atoms, respectively. Trifluoromethyl radicals were produced through the thermal dissociation of CF 3 I. The rate coefficients for the reactions CF 3 + O( 3 P) f CF 2 O + F (1b) and CF 3 + H f CF 2 ( 1 A 1 ) + HF (2c) were obtained from the decay profiles of O-and H-atom concentrations as k 1b ) (2.55(0.23) × 10 -11 and k 2c ) (8.86(0.32) × 10 -11 cm 3 molecule -1 s -1 (error limits at the one standard deviation level). Neither rate coefficient had any temperature or pressure dependence under the present experimental conditions; the values were in good agreement with some room-temperature data reported previously.

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