Yields of O₂(b¹Σ) from reactions of HO₂

A discharge‐flow apparatus with resonance fluorescence and chemiluminescence detection has been used to monitor O 2 ( b 1 σ ) production from several reactions of the HO 2 radical at 300 K and 1‐torr total pressure. O 2 (b), HO 2 , and OH were observed when F atoms were added to H 2 O 2 in the gas phase. Signal strengths of O 2 (b) were proportional to initial concentrations of H 2 O 2 and HO 2 . These observations were analyzed by using a simple three step mechanism and a more complete computer simulation with 22 reaction steps. The results indicate that the F + HO 2 reaction yields O 2 (b) with an efficiency of (3.6 ± 1.4) × 10 −3 . By monitoring [O 2 (b)] and [HO 2 ] upon addition of an excess second reactant to HO 2 , O 2 (b) yields from the reactions of HO 2 with O, Cl, D, H, and OH were found to be <1 × 10 −2 , <5 × 10 −4 , <2 × 10 −3 , <8 × 10 −3 , and <1 × 10 −3 , respectively. Yields of O 2 (b) from the HO 2 ± HO 2 reaction were found to be less than 3 × 10 −2 .