Hydrogen chloride-induced surface disordering on ice
- V. Faye McNeill*,†,
- Thomas Loerting‡,§,¶,
- Franz M. Geiger‡,§,‖,
- Bernhardt L. Trout*, and
- Mario J. Molina‡,§,**
- Departments of ‡Chemistry,
- §Earth, Atmospheric, and Planetary Sciences, and
- *Chemical Engineering, Massachusetts Institute of Technology, Cambridge, MA 02139
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Contributed by Mario J. Molina, May 4, 2006
Abstract
Characterizing the interaction of hydrogen chloride (HCl) with polar stratospheric cloud ice particles is essential for understanding the processes responsible for ozone depletion. We studied the interaction of gas-phase HCl with ice between 243 and 186 K by using (i) ellipsometry to monitor the ice surface and (ii) coated-wall flow tube experiments, both with chemical ionization mass spectrometry detection of the gas phase. We show that trace amounts of HCl induce formation of a disordered region, or quasi-liquid layer, at the ice surface at stratospheric temperatures. We also show that surface disordering enhances the chlorine activation reaction of HCl with chlorine nitrate (ClONO2) and also enhances acetic acid (CH3COOH) adsorption. These results impact our understanding of the chemistry and physics of ice particles in the atmosphere.
Footnotes
- **To whom correspondence should be sent at the present address: Department of Chemistry, University of California at San Diego, La Jolla, CA 92093-0356. E-mail: mjmolina{at}ucsd.edu
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↵ †Present address: Department of Atmospheric Sciences, University of Washington, Seattle, WA 98195.
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↵ ¶Present address: Institute of Physical Chemistry, Institute of General, Inorganic, and Theoretical Chemistry, University of Innsbruck, A-6020 Innsbruck, Austria.
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↵ ‖Present address: Department of Chemistry, Northwestern University, Evanston, IL 60208.
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Author contributions: M.J.M. designed research; V.F.M., T.L., and F.M.G. performed research; V.F.M., T.L., F.M.G., B.L.T., and M.J.M. analyzed data; and V.F.M. wrote the paper.
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Conflict of interest statement: No conflicts declared.
- Abbreviations:
- QLL,
- quasi-liquid layer;
- CIMS,
- chemical ionization mass spectrometry;
- PHCl,
- HCl partial pressure.
Abbreviations:
- © 2006 by The National Academy of Sciences of the USA
