Kinetics and product studies of the BrO + ClO Reaction: Implications for Antarctic chemistry

• Published in: Geophysical Research Letters
• Main Authors: Sander, Stanley P., Friedl, Randall R.
• Format: Article in Journal/Newspaper
• Language: unknown
• Published: American Geophysical Union 1988
• Subjects: Antarc*; Antarctic
• Online Access: https://doi.org/10.1029/gl015i008p00887

The reaction of ClO with BrO has been investigated by two independent techniques, discharge flowâ€mass spectrometry and flash photolysisâ€UV spectrometry, over the temperature range 220â€400 K and the pressure range 1â€760 torr. Rate constants have been determined for three product channels; a) Br + ClOO, b) Br + OClO, and c) BrCl + O_2. The rate constants for the overall reaction and each reaction branch were found to be inversely dependent on temperature and independent of pressure. The results for the temperature dependence of the overall rate constant from the discharge flow and flash photolysis studies are in excellent agreement, and collectively disagree substantially with the only previous temperature dependence study. Also, in contrast to previous studies, the channel forming BrCl is found to be significant (≃ 8%). These kinetic measurements have an important impact on the modeling of Antarctic chemistry; for temperatures found in the Antarctic stratosphere the rate coefficients for the channels yielding ClOO and OClO are a factor of 2â€3 larger than previously estimated. In addition, the BrCl channel, which has an impact on the nighttime partitioning of BrO_X and the diurnal variability of OClO, has been omitted from previous atmospheric models. © 1988 American Geophysical Union. (Received: May 12, 1988; Revised: June 28, 1988; Accepted: June 30, 1988) Paper number 8L6857. The authors wish to thank Drs. D. W. Toohey and R. J. Salawitch for many helpful discussions. The research described in this paper was carried out at the Jet Propulsion Laboratory, California Institute of Technology, under contract with the National Aeronautics and Space Administration. This article also appears in: Polar Ozone Published - Sander_et_al-1988-Geophysical_Research_Letters.pdf