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Kinetics and product studies of the BrO + ClO Reaction: Implications for Antarctic chemistry
Author(s) -
Sander Stanley P.,
Friedl Randall R.
Publication year - 1988
Publication title -
geophysical research letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.007
H-Index - 273
eISSN - 1944-8007
pISSN - 0094-8276
DOI - 10.1029/gl015i008p00887
Subject(s) - reaction rate constant , flash photolysis , photodissociation , torr , chemistry , kinetic energy , stratosphere , analytical chemistry (journal) , kinetics , reaction rate , atmospheric temperature range , mass spectrometry , atmospheric chemistry , chemical kinetics , environmental chemistry , thermodynamics , ozone , atmospheric sciences , photochemistry , organic chemistry , chromatography , geology , catalysis , physics , quantum mechanics
The reaction of ClO with BrO has been investigated by two independent techniques, discharge flow‐mass spectrometry and flash photolysis‐UV spectrometry, over the temperature range 220‐400 K and the pressure range 1‐760 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 2‐3 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.