Reaction ii H O2 OH

Values of k2 from a variety of sources have already been presented in Sect. 3.6 and 5.2, and in Tables 15, 24, 28 and 29. Some additional data from low pressure flame studies is given in Table 37. There is also a considerable body of data from shock tube investigations, reported by Baulch et al. [55], for which it is not clear that corrections were applied for boundary layer effects in the shock tube (see Sect. 5.1). This data has been omitted from consideration here — although much of it is in reasonable accord with the expression recommended below for 

0 X 10 1052 [H2 0] by freezing down in calibrated volume. Assumed all oxygen consumed by reaction (ii).  

5 X 10 905 calibrated volume. Extent of isotopic exchange related to competition of reaction (ii) with isotopic exchange H + Dj - HD + D to give ratio of rate coefficients. Values for fe2 are  

Extrapolating eqn. (72) towards lower temperatures gives 2 = 0.163 at 300 K, and dividing this by the equilibrium constant K2 = 1.0 x 10 leads to fe 2 = 1-63 x 10 at this temperature. Direct measurements on the reverse reaction by discharge-flow techniques [175, 220—223] have given k 2 = (2.3 1.0) x 10 at 300 K. 

O atoms from N + NO. [O] and [H2 ] estimated by ESR and mass spectrometry. H2 added through moveable inlet. Observed rate coefficients divided by 2 to allow for fast consecutive reaction 

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