Pressure and Temperature Dependencies of Rate Coefficients for the Reaction OH + NO₂ + M → Products
Abstract
The OH + NO₂ reaction is a critically important process for radical chain termination in the atmosphere with a major impact on the ozone budgets of the troposphere and stratosphere. Rate constants for the reaction of OH + NO₂ + M → products have been measured under conditions relevant to the upper troposphere/lower stratosphere with a laser photolysis–laser-induced fluorescence (LP-LIF) technique augmented by in situ optical spectroscopy for quantification of [NO₂]. The experiments are carried out over the temperature range of 230–293 K and the pressure range 50–750 Torr of N₂ and air and as a function of [O₂]. The observed rate coefficients in N₂ agree with the newest experimental literature data sets and are within experimental uncertainty of current recommended literature values at 293 K but are systematically higher by up to 22% at 700 Torr and 230 K. The efficacy of different falloff parametrizations has been examined and compared to those in literature sources. The collisional quenching efficiency of O₂ was found to be in excellent agreement with current literature sources, and rate coefficients determined in air at 293 and 245 K were observed to be within uncertainty of the rate coefficients measured in N₂ bath gas. This work has improved confidence in the literature rate coefficients under conditions of the lower troposphere (∼760 Torr, 280–310 K) toward the stratosphere (10–100 Torr, 220–250 K).
Additional Information
© 2020 American Chemical Society. Received: September 30, 2020; Revised: October 29, 2020; Published: December 1, 2020. K.Z. was supported by an appointment to the NASA Postdoctoral Program at the NASA Jet Propulsion Laboratory, administered by Universities Space Research Association under a contract with NASA. Support from the NASA Upper Atmosphere Research and Tropospheric Composition Programs is gratefully acknowledged. The authors declare no competing financial interest.Attached Files
Supplemental Material - jp0c08920_si_001.pdf
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Additional details
- Alternative title
- Pressure and Temperature Dependencies of Rate Coefficients for the Reaction OH + NO2 + M → Products
- Eprint ID
- 107014
- Resolver ID
- CaltechAUTHORS:20201210-133602227
- NASA Postdoctoral Program
- NASA/JPL
- Created
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2020-12-10Created from EPrint's datestamp field
- Updated
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2021-11-16Created from EPrint's last_modified field