Rate constants for the reaction, O(3P)+H2O¶OH+OH, over the temperature range 1053 K to 2033 K using two direct techniques

The rate constant for the reaction of O( 3 P) with H 2 O (reaction (1)) was measured over the temperature range 1288 K≤T≤2033 K using the flash photolysis-shock tube technique and at 1053, 1090 and 1123 K using the flash photolysis-resonance fluorescence method. The photolytic source for O( 3 P) atoms was nitric oxide. The results were given by the Arrhenius expression: k 1 (T)=(9.2±0.9)×10 −11 exp(−19100±300 cal mol −1 /RT) cm 3 molecule −1 s −1 The present results were equally well fit to the three parameter expression: k 1 (T)=4.93×10 −18 T 2.02 exp(−13400 cal mol −1 /RT) cm 3 molecule −1 s −1 . Uncertainties in the Arrhenius expressions are given at the one standard deviation level and the mean deviation of the data from each expression is ±16%. Corresponding rate constants for the reverse reaction (reaction (−1)) were computed from the known values of the equilibrium constant and were fitted to the Arrhenius equation: k −1 (T)=(8.9±0.9)×10 −12 exp(−2100±300 cal mol −1 /RT) cm 3 molecule −1 s −1 . These direct experimental results for k −1 (T) and k 1 (T) are compared with previously reported experimental measurements and with available theoretical expressions.