Reactions of HO2 studied by flash photolysis with diode-laser spectroscopy

Abstract

Tunable diode lasers make it possible to record the infrared spectra of transient species at Doppler-limited resolution on time-scales of <1 ms. This technique has been combined with flash photolysis to study reactions of the HO₂ radical. Studies of the recombination of HO₂ radicals at total pressures between 7 and 20 Torr give rate coefficients in the range (1.5–2.0) x 10^–12 cm³ s^–1 at 305 K for oxygen carriers. These values are significantly lower than other workers have found near atmospheric pressure. They support the view that this reaction yields H₂O₂+ O₂ by two parallel paths, one a direct disproportionation the other involving an H₂O₄ intermediate.