Kinetics of the reaction of HO₂ with NO

Abstract

The gas phase reaction of HO 2 radicals with NO was studied using a discharge‐flow system and laser‐magnetic resonance detection. Concentrations of HO 2 down to 2 × 10 9 molecules/cm³ were detectable, thus allowing the reaction to be studied under pseudo‐first‐order kinetic conditions. The rate constant was measured using three independent kinetic schemes, one of which involved the detection of the reaction products OH and NO 2 . The three schemes gave results in excellent agreement. The rate constant, k 1 , for the reaction urn:x-wiley:00948276:media:grl591:grl591-math-0001 is (8.1 ± 1.5) × 10 −12 cm³/molecule·s at 296K and a pressure of 140‐220 Pa (1.1‐1.7 torr). The measurements also indicate that the rate constants for two other exothermic channels of the reaction are less than 2% of k 1 .