A theoretical study of the reaction of ClONO2 with HCl on ice

Citation
R. Bianco et Jt. Hynes, A theoretical study of the reaction of ClONO2 with HCl on ice, J PHYS CH A, 103(20), 1999, pp. 3797-3801
Citations number
53
Categorie Soggetti
Physical Chemistry/Chemical Physics
Journal title
JOURNAL OF PHYSICAL CHEMISTRY A
ISSN journal
10895639 → ACNP
Volume
103
Issue
20
Year of publication
1999
Pages
3797 - 3801
Database
ISI
SICI code
1089-5639(19990520)103:20<3797:ATSOTR>2.0.ZU;2-Z
Abstract
The direct ClONO2 + HCl --> Cl-2 + HNO3 reaction on ice, implicated in pola r stratospheric ozone depletion, is studied quantum chemically on a model i ce lattice comprising nine water molecules. The reaction path is calculated at the HF/(HW*,3-21G) level, using the Hay-Wadt effective core potential f or Cl. At these geometries, energies are recalculated at the MP2/(SBK+*,6-3 1+G*) 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 kc al/mol. The reaction mechanism involves proton transfer in the ice lattice, accompanied by nucleophilic attack of Cl- on the Cldelta+ in ClONO2; the l attice is an active participant in the reaction. Implications for heterogen eous atmospheric chemistry are discussed.