A theoretical study of the reaction of ClONO{sub 2} with HCl on ice

Journal Article · Thu May 20 04:00:00 EDT 1999 · Journal of Physical Chemistry A: Molecules, Spectroscopy, Kinetics, Environment, amp General Theory

DOI:https://doi.org/10.1021/jp990471b· OSTI ID:355558

Bianco, R; Hynes, J T ^[1]

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1. Univ. of Colorado, Boulder, CO (United States). Dept. of Chemistry and Biochemistry

Since the proposal that ice particles in Antarctic polar stratospheric clouds could be responsible for the reactivation of chlorine from the so-called reservoir species ClONO{sub 2} and HCl, numerous experimental studies have demonstrated the remarkable efficiency of the reactions. The direct ClONO{sub 2} + HCl {r_arrow} Cl{sub 2} + HNO{sub 3} reaction on ice, implicated in polar stratospheric ozone depletion, is studied quantum chemically on a model ice lattice comprising nine water molecules. The reaction path is calculated at the HF/(HW{sup *},3-21G) level, using the Hay-Wadt effective core potential for Cl. At these geometries, energies are recalculated at the MP2/(SBK+{sup *},6-31+G{sup *}) level, with the Stevens-Bash-Krauss effective core potential for Cl. HCl is found to be ionized in the reactant complex. The calculated reaction internal energy barrier, including zero-point energy correction, is 6.4 kcal/mol. The reaction mechanism involves proton transfer in the ice lattice, accompanied by nucleophilic attack of Cl{sup {minus}} on the Cl{sup {delta}+} in ClONO{sub 2}; the lattice is an active participant in the reaction. Implications for heterogeneous atmospheric chemistry are discussed.

• OSTI ID: 355558
• Journal Information: Journal of Physical Chemistry A: Molecules, Spectroscopy, Kinetics, Environment, amp General Theory, Journal Name: Journal of Physical Chemistry A: Molecules, Spectroscopy, Kinetics, Environment, amp General Theory Journal Issue: 20 Vol. 103; ISSN 1089-5639; ISSN JPCAFH
• Country of Publication: United States
• Language: English

Related Subjects

54 ENVIRONMENTAL SCIENCES
ATMOSPHERIC CHEMISTRY
HYDROCHLORIC ACID
ICE
MATHEMATICAL MODELS
NITRIC ACID
OZONE LAYER