TEMPERATURE-DEPENDENCE OF THE RATE COEFFICIENT OF THE REACTION OH-424-K(CF3CH2F OVER THE RANGE 255)

The rate coefficient of the reaction of OH with CF3CH2F at six tempera tures in the range 255-424 K was determined by means of the discharge- flow/resonance-fluorescence technique. The resonance fluorescence of O H, excited by emission from a gaseous mixture of H2O and He subjected to a microwave discharge, was detected by photon-counting technique. T he reaction was carried out under pseudo-first-order conditions with [ CF3CH2F] >> [OH]; the late coefficient was determined to be k = (3.9+/ -0.6) x 10(-15) cm(3) molecule(-1) s(-1) at 298 K; the uncertainty rep resents the 95% confidence limit. The temperature dependence of the ra te coefficient is expressed in the Arrhenius form, k(T) = (9.9+/-1.0) x 10(-13) exp [-(1640+/-150)/T] cm(3) molecule(-1) s(-1).