Kinetics and temperature dependence of the BrO + ClO reaction

Journal Article · Thu May 30 04:00:00 EDT 1991 · Journal of Physical Chemistry; (United States)

DOI:https://doi.org/10.1021/j100164a035· OSTI ID:5890248

Turnipseed, A A; Birks, J W ^[1]; Calvert, J G ^[2]

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1. Univ. of Colorado, Boulder (United States)
2. National Center for Atmospheric Research, Boulder, CO (United States)

The kinetics of the BrO + ClO reaction was studied over the temperature range 234-406 K by discharge flow/mass spectrometry. The total rate constant for the reaction was found to have a significant negative activation energy and is given by k{sub 1}(T) = (2.59 {plus minus} 0.36) {times} 10{sup {minus}12} exp((445 {plus minus} 84)/T) cm{sup 3} molecule{sup {minus}1} s{sup {minus}1}. The reaction has three product channels: (a) ClOO + Br, (b) OClO + Br, and (c) BrCl + O{sub 2}. The branching ratios for the three channels as a function of temperature were measured, and it was found that the channel leading to formation of OClO becomes dominant at lower temperatures (branching ratio of 0.51 at 250 K). Evidence for the direct formation of BrCl was found, yielding a branching ratio of 0.09-0.10 for the BrCl channel over the temperature range 250-406 K. The temperature-dependent rate coefficients for the three channels are given by k{sub 1a} = (2.1 {plus minus} 0.4) {times} 10{sup {minus}12} exp((258 {plus minus} 56)/T), k{sub 1b} = (6.7 {plus minus} 1.0) {times} 10{sup {minus}13} exp((622 {plus minus} 94)/T), and k{sub 1c} = (1.9 {plus minus} 0.6) {times} 10{sup {minus}13} exp((513 {plus minus} 86)/T) cm{sup 3} molecule{sup {minus}1} s{sup {minus}1}. These results are discussed relative to other recent studies and their importance in understanding the stratospheric chemistry of the Antarctic ozone hole.

• OSTI ID: 5890248
• Journal Information: Journal of Physical Chemistry; (United States), Journal Name: Journal of Physical Chemistry; (United States) Vol. 95:11; ISSN 0022-3654; ISSN JPCHA
• Country of Publication: United States
• Language: English

Related Subjects

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
400201* -- Chemical & Physicochemical Properties
54 ENVIRONMENTAL SCIENCES
540120 -- Environment
Atmospheric-- Chemicals Monitoring & Transport-- (1990-)
ACTIVATION ENERGY
ATMOSPHERIC CHEMISTRY
BRANCHING RATIO
BROMINE CHLORIDES
BROMINE COMPOUNDS
BROMINE OXIDES
CHALCOGENIDES
CHEMICAL REACTION KINETICS
CHEMICAL REACTIONS
CHEMISTRY
CHLORIDES
CHLORINE COMPOUNDS
CHLORINE OXIDES
EARTH ATMOSPHERE
ELECTRIC DISCHARGES
ENERGY
HALIDES
HALOGEN COMPOUNDS
HIGH-FREQUENCY DISCHARGES
KINETICS
MASS SPECTROSCOPY
OXIDES
OXYGEN COMPOUNDS
OZONE
RADICALS
REACTION KINETICS
SPECTROSCOPY
STRATOSPHERE
TEMPERATURE RANGE
TEMPERATURE RANGE 0065-0273 K
TEMPERATURE RANGE 0273-0400 K
TEMPERATURE RANGE 0400-1000 K