The rate constant for the recombination reaction between CF3 and O-2 measured between 2 and 110 Torr

The rate constant k(1) for the recombination reaction between CF3 radicals and O-2 has been measured at 295 K over the pressure range of 2-110 Torr, p redominately in N-2. CF3 radicals were formed by the uv photolysis of CF3I, and their kinetic decay monitored in the presence of NO2 and O-2 by observ ing the infrared emission from the products of the: CF3 + NO2 reaction. The data were combined with higher pressure relative rate constant measurement s in the literature to yield a fall off curve with the high pressure limiti ng value of k(1(infinity)) = (2.55 +/- 0.11) . 10(-12) cm(3) molecule(-1) s (-1) and the low pressure third body recombination rate constant k(1(0)) = (2.5 +/- 0.3) . 10(-29) cm(6) molecule(-2) s(-1) with 2 sigma quoted errors . and the Tree broadening parameter F-c = 0.60. The high pressure limiting value is some 35% lower than the currently recommended value, but is believ ed to be more reliable because of the far shorter extrapolation to the high pressure limit in the present study compared with previous work. Our data also suggest a reevaluation of the bimolecular rate constant of the CF3 + C l-2 reaction to (2.3 +/- 0.6) . 10(-14) cm(3) moletule(-1) s(-1).