The reaction of O( 1 D ) with H 2 O and the reaction of OH with C 3 H 6

N 2 O was photolyzed at 2139 Å to produce O( 1 D ) atoms in the presence of H 2 O and CO. The O( 1 D ) atoms react with H 2 O to produce HO radicals, as measured by CO 2 production from the reaction of OH with CO. The relative importance of the various possible O( 1 D )–H 2 O reactions isThe relative rate constant for O( 1 D ) removal by H 2 O compared to that by N 2 O is 2.1, in good agreement with that found earlier in our laboratory. In the presence Of C 3 H 6 , the OH can be removed by reaction with either CO or C 3 H 6 :From the CO 2 yield, k 3 / k 2 = 75,0 at 100°C and 55.0 at 200°C to within ± 10%. When these values are combined with the value of k 2 = 7.0 × 10 −13 exp (–1100/ RT ) cm 3 /sec, k 3 = 1.36 × 10 −11 exp (–100/ RT ) cm 3 /sec. At 25°C, k 3 extrapolates to 1.1 × 10 −11 cm 3 /sec.