The reaction of O(1D) with H2O and the reaction of OH with C3H6

N₂O was photolyzed at 2139 Å to produce O(¹D) atoms in the presence of H₂O and CO. The O(¹D) atoms react with H₂O to produce HO radicals, as measured by CO₂ production from the reaction of OH with CO. The relative importance of the various possible O(¹D )–H₂O reactions is The relative rate constant for O(¹D) removal by H₂O compared to that by N₂O is 2.1, in good agreement with that found earlier in our laboratory. In the presence Of C₃H₆, the OH can be removed by reaction with either CO or C₃H₆: From the CO₂ yield, k₃/k₂ = 75,0 at 100°C and 55.0 at 200°C to within ± 10%. When these values are combined with the value of k₂ = 7.0 × 10^?13exp (–1100/RT) cm³/sec, k₃ = 1.36 × 10^?11 exp (–100/RT) cm³/sec. At 25°C, k₃ extrapolates to 1.1 × 10^?11 cm³/sec.