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Kinetics of HO_2 + HO_2 → H_2O_2 + O_2: Implications for Stratospheric H_2O_2

Christensen, L. E. and Okumura, M. and Sander, S. P. and Salawitch, R. J. and Toon, G. C. and Sen, B. and Blavier, J.-F. and Jucks, K. W. (2002) Kinetics of HO_2 + HO_2 → H_2O_2 + O_2: Implications for Stratospheric H_2O_2. Geophysical Research Letters, 29 (9). Art. No. 1299. ISSN 0094-8276. doi:10.1029/2001GL014525.

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The reaction HO_2 + HO_2 → H_2O_2 + O_2(1) has been studied at 100 Torr and 222 K to 295 K. Experiments employing photolysis of Cl_2/CH_3OH/O_2/N_2 and F_2/H_2/O_2/N_2 gas mixtures to produce HO_2 confirmed that methanol enhanced the observed reaction rate. At 100 Torr, zero methanol, k_1 = (8.8 ± 0.9) 10^(−13) × exp[(210 ± 26)/T] cm^3 molecule^(−1) s^(−1) (2σ uncertainties), which agrees with current recommendations at 295 K but is nearly 2 times slower at 231 K. The general expression for k_1, which includes the dependence on bath gas density, is k_1 = (1.5 ± 0.2) × 10^(−12) × exp[(19 ± 31)/T] + 1.7 × 10^(−33) × [M] × exp[1000/T], where the second term is taken from the JPL00-3 recommendation. The revised rate largely accounts for a discrepancy between modeled and measured [H_2O_2] in the lower to middle stratosphere.

Item Type:Article
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URLURL TypeDescription
Okumura, M.0000-0001-6874-1137
Sander, S. P.0000-0003-1424-3620
Toon, G. C.0000-0003-4174-7541
Alternate Title:Kinetics of HO2 + HO2 → H2O2 + O2: Implications for Stratospheric H2O2
Additional Information:Copyright 2002 by the American Geophysical Union. Received 6 December 2001; accepted 28 December 2001; published 7 May 2002. This work was supported by the NASA Upper Atmosphere Research and Tropospheric Chemistry Programs and the NASA Graduate Student Researchers Program (GRSP). We wish to thank The National Scientific Balloon Facility (NSBF), Palestine, TX, for use of their facility and resources for the MkIV and FIRS-2 instruments. We also wish to thank D. J. Jacob and F. Ravetta for insight into the effect of k_1 on tropospheric chemistry, J. S. Francisco and J. C. Hansen for calculations regarding hydrogen-bonding between methanol and HO_2, and D. B. Natzic for his invaluable experimental contributions. This research was carried out at the Jet Propulsion Laboratory, California Institute of Technology, under contract with the National Aeronautics and Space Administration.
Funding AgencyGrant Number
NASA Graduate Student Research FellowshipUNSPECIFIED
Subject Keywords:Atmospheric Composition and Structure: Constituents sources and sinks; Chemical kinetic and photochemical properties; Middle atmosphere: composition and chemistry
Issue or Number:9
Record Number:CaltechAUTHORS:20141027-085804530
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Official Citation:Christensen, L. E., M. Okumura, S. P. Sander, R. J. Salawitch, G. C. Toon, B. Sen, J. F. Blavier, and K. W. Jucks, Kinetics of HO2 + HO2 [RIGHTWARDS ARROW] H2O2 + O2: Implications for Stratospheric H2O2, Geophys. Res. Lett., 29(9), doi:10.1029/2001GL014525, 2002
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:50825
Deposited By: George Porter
Deposited On:27 Oct 2014 16:33
Last Modified:10 Nov 2021 19:01

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