Kinetic and mechanistic study of the reaction of O(1D) with CF2HBr

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(D-1), with CF2HBr. Absolute rate coefficients (k(1)) for the deactivation of O(D-1) by CF2HBr 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 x 10(10) exp(+72/T) cm(3)molecule(-1) s(-1); the accuracy of each reported rate coefficient is estimated to be +/- 15% (2 sigma). The branching ratio for nonreactive quenching of O(D-1) to the ground state, O(P-3), 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(D-1) + CF2XY reactions (X, Y = H, F, Cl, Br). (C) 2001 John Wiley & Sons. Inc.