Molecular activation by surface coordination: New model for HCl reactivity on water-ice polar stratospheric clouds
- Pennsylvania State Univ., University Park, PA (United States). Dept. of Chemistry
The annual depletion of the ozone layer in the polar stratosphere has received considerable scrutiny, particularly in the area of conversion chemistry involving chlorine. Numerous studies have implicated polar stratospheric clouds (PSCs) as playing a fundamental role in the conversion of reservoir chlorine species, such as HCl and ClONO{sub 2}, into active forms of chlorine such as Cl{sub 2} Results of studies of the uptake of HCl by the deuterated analogue of protonated water clusters are reported. The successive uptake of nHCl n = 1--4 is observed, n = 2--4 appearing in a stepwise manner with a ratio of 6:1 D{sub 2}O/HCl for the bimolecular reaction products. This primary uptake scheme is observed over a range of pressures and temperatures. However, for increased flows of HCl, enhanced uptake is observed at a lower ratio of D{sub 2}O/HCl, a trend that is effected by an increased buffer gas pressure. Two distinctly dominant mechanisms of HCl uptake are operative: the bimolecular uptake of HCl in a 6:1 ratio with water and a subsequent association mechanism of HCl binding to water in a 3:1 ratio. The atmospheric implications are discussed along with a proposed molecular activation by surface coordination (MASC) model for HCl uptake and subsequent reactivity on polar stratospheric clouds.
- OSTI ID:
- 355561
- Journal Information:
- Journal of Physical Chemistry A: Molecules, Spectroscopy, Kinetics, Environment, amp General Theory, Vol. 103, Issue 21; Other Information: PBD: 27 May 1999
- Country of Publication:
- United States
- Language:
- English
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