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1996
Conference Paper
Titel
HO2 + NO revisited first rate constants at tropospheric pressures
Abstract
The rate constant of this reaction is required to model - in the atmosphere and in laboratory experiments - its competition with chain terminating reactions (HO2 + OH, HO2 + RO2) affecting the oxidation potential of the troposphere, and with other NO-consuming reactions (RO2 +NO): where NO is scarce, the product distribution depends on whether HO2 or RO2 reacts with NO. While the negative temperature dependence suggests also a pressure dependence, the current recommendation for this important reaction relies solely on low-pressure data from discharge flow experiments. In this work, i present flash photolysis/resonance fluorescence experiments (FP/RF) in the temperature range 254-422 K and up to 970 mbar He. Several tests showed both radical-radical reactions and background OH to be unimportant. The obtained OH kinetics is well described by a global fit (first-order rate constants constrained to be linear in NO).
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