Kinetic and mechanistic study of the reaction of O( 1 D) with CF 2 HBr

A laser flash photolysis–resonance fluorescence technique has been employed to investigate the kinetics and mechanism of the reaction of electronically excited oxygen atoms, O( 1 D), with CF 2 HBr. Absolute rate coefficients ( k 1 ) for the deactivation of O( 1 D) by CF 2 HBr have been measured as a function of temperature over the range 211–425 K. The results are well described by the Arrhenius expression k 1 (T) = 1.72 × 10 −10 exp(+72/T) cm 3 molecule −1 s −1 ; the accuracy of each reported rate coefficient is estimated to be ±15% (2σ). The branching ratio for nonreactive quenching of O( 1 D) to the ground state, O( 3 P), is found to be 0.39 ± 0.06 independent of temperature, while the branching ratio for production of hydrogen atoms at 298 K is found to be 0.02 −0.02 +0.01 . The above results are considered in conjunction with other published information to examine reactivity trends in O( 1 D) + CF 2 XY reactions (X,Y = H, F, Cl, Br). © 2001 John Wiley & Sons, Inc. Int J Chem Kinet 33: 262–270, 2001