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The reaction O((3)P) + HOBr: Temperature dependence of the rate constant and importance of the reaction as an HOBr stratospheric loss processThe absolute rate constant for the reaction O((3)P) + HOBr has been measured between T = 233K and 423K using the discharge-flow kinetic technique coupled to mass spectrometric detection. The value of the rate coefficient at room temperature is (2.5 +/- 0.6) x 10(exp -11)cu cm/molecule/s and the derived Arrhenius expression is (1.4 +/- 0.5) x 10(exp -10) exp((-430 +/- 260)/T)cu cm/molecule/s. From these rate data the atmospheric lifetime of HOBr with respect to reaction with O((3)P) is about 0.6h at z = 25 km which is comparable to the photolysis lifetime based on recent measurements of the UV cross section for HOBr. Implications for HOBr loss in the stratosphere have been tested using a 1D photochemical box model. With the inclusion of the rate parameters and products for the O + HOBr reaction, calculated concentration profiles of BrO increase by up to 33% around z = 35 km. This result indicates that the inclusion of the O + HOBr reaction in global atmospheric chemistry models may have an impact on bromine partitioning in the middle atmosphere.
Document ID
19950056383
Document Type
Reprint (Version printed in journal)
External Source(s)
Authors
Nesbitt, F. L. (NASA Goddard Space Flight Center Greenblet, MD, United States)
Monks, P. S. (NASA Goddard Space Flight Center Greenblet, MD, United States)
Payne, W. A. (NASA Goddard Space Flight Center Greenblet, MD, United States)
Stief, L. J. (NASA Goddard Space Flight Center Greenblet, MD, United States)
Toumi, R. (Imperial College London, United Kingdom)
Date Acquired
August 16, 2013
Publication Date
April 1, 1995
Publication Information
Publication: Geophysical Research Letters
Volume: 22
Issue: 7
ISSN: 0094-8276
Subject Category
METEOROLOGY AND CLIMATOLOGY
Distribution Limits
Public
Copyright
Other