VUV Flash Photolysis Study of the Reaction of HO with HO₂ at 1 atm and 298 K

Equal concentrations of HO and H were generated by flash photolysing small amounts of H 2 O diluted in N 2 at a pressure of about one atmosphere. Using sensitive detection by resonance absorption, the HO radicals were monitored in the presence and in the absence of O 2 . In the presence of O 2 , the radicals were found to disappear significantly faster than in the absence of O 2 . This enhanced decay is attributed to the fast reaction of HO with HO 2 . Using simple kinetic arguments and computer modeling, the rate constant, k 1 , for the title reaction is estimated to be 1.1 · 10 −10 cm 3 s −1 (+25%; −35%).