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GEOPHYSICAL RESEARCH LETTERS,
VOL. 26, NO. 6,
PAGES 687–690,
1999
Temperature and Pressure Dependent Kinetics of the Gas-Phase Reaction of the Hydroxyl Radical with Nitrogen Dioxide
Timothy J. Dransfield
Department of Chemistry and Chemical Biology, Harvard University, Cambridge, Massachusetts
Katherine K. Perkins
Department of Chemistry and Chemical Biology, Harvard University, Cambridge, Massachusetts
Neil M. Donahue
Department of Chemistry and Chemical Biology, Harvard University, Cambridge, Massachusetts
James G. Anderson
Department of Chemistry and Chemical Biology, Harvard University, Cambridge, Massachusetts
Michele M. Sprengnether
Department of Earth and Atmospheric Sciences, Atmospheric Sciences Research Center, SUNY, Albany
Kenneth L. Demerjian
Department of Earth and Atmospheric Sciences, Atmospheric Sciences Research Center, SUNY, Albany
Abstract
The reaction of OH with NO2 is pivotal in both stratospheric and tropospheric chemistry; in each case it is the dominant homogeneous mechanism for conversion
of NO x to NO y . The rate constant is a strong function of pressure and temperature, and key portions of the pressure-temperature domain
are poorly or ambiguously covered by the available data. These include conditions typical of the tropospheric boundary layer
and of the lower stratosphere. At surface conditions differences of 60% exist both in the literature data and between the
major recommendations, while at lower stratospheric conditions there are few available data. Our High Pressure Flow kinetics
system is ideally suited to studying this reaction, as we are able to scan both temperature and pressure while maintaining
wall-less conditions, eliminating the possible complications of heterogeneous chemistry. Here we report a temperature- and
pressure-dependent study (220 - 300 K, 50 - 150 torr) of this reaction; the measured rate constants are in excellent agreement
with previously published values down to 240 K, but lie 10-20% lower than the historical data available below that temperature.
An analysis of all available data motivates a large (∼ 20%) downward revision in the recommended rate constant below room
temperature.
Received 7
October
1998;
accepted 4
January
1999.
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Citation: Dransfield, T. J., K. K. Perkins, N. M. Donahue, J. G. Anderson, M. M. Sprengnether, and K. L. Demerjian
(1999),
Temperature and Pressure Dependent Kinetics of the Gas-Phase Reaction of the Hydroxyl Radical with Nitrogen Dioxide,
Geophys. Res. Lett.,
26(6),
687–690.
Copyright 1999 by the American Geophysical Union.
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