Reaction of HO2 with O3.

Description of an experiment in which HO2 radicals were produced from the photolysis of O3 at 2537 A in the presence of excess H2 and O2. The O(1 D) atoms produced from the photolysis of O3 react with H2 to produce HO radicals and H atoms. The HO radicals react with H2 to give H2O and more H atoms. All the H atoms then add to O2 to produce HO2 radicals. The quantum yield of O3 removal is measured, and from this measurement the importance of the reaction between HO2 and O3 to yield HO plus 2O2 is determined.