O( 3 P ) + HOONO 2 → products: Temperature‐dependent rate constant

The title reaction was studied in a stirred‐flow reactor at six temperatures ranging from 228 to 297 K and for pressures near 2 torr. The experiments were performed under O‐atom‐rich conditions, and the HOONO 2 concentration was monitored with a modulated molecular‐beam mass spectrometer. O‐atom concentrations were measured by titration with NO 2 and by monitoring the portion of O 2 dissociated in the microwave discharge. A weighted least‐squares analysis gives ( k ± 1σ) = (7.0 ± 12.2) × 10 −11 exp(‐3369 ± 489/ T ) cm 3 /s, where the uncertainties are 1 standard deviation (six temperatures) the covariance was σ AB = 5.97 × 10 −8 . Due to the possible presence of systematic errors, the uncertainty in the rate constant could be as great as a factor of 2 over the entire temperature range.