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Title: Exploration of the mechanism of the activation of ClONO{sub 2} by HCl in small water clusters using electronic structure methods

Abstract

High-level electronic structure calculations were used to study the mechanism of the reaction of ClONO{sub 2} with HCl in neutral water clusters containing one to five solvating water molecules. For the reaction between molecular HCl and ClONO{sub 2}, the barrier decreases from 42 kcal mol{sup {minus}1} (uncatalyzed) to essentially zero when catalyzed by only two water molecules, where the reaction products involve Cl{sub 2} and HONO{sub 2}. The calculations thus predict that the gas-phase reaction may be important in the stratospheric reactivation of ClONO{sub 2}. The reaction between ClONO{sub 2} and solvated H{sub 3}O{sup +}Cl{sup {minus}}, as on the polar stratospheric cloud (PSC) surface, was investigated with clusters involving up to seven water molecules. The ice-catalyzed reaction involves an ionic mechanism whereby charge transfer to ClONO{sub 2} from the attacking nucleophile leads to significant ionization along the Cl-ONO{sub 2} bond. The effect of the size of the first solvation shell of Cl{sup {minus}} is addressed by the calculations. In a cluster containing three waters and a five-water cluster structurally related to hexagonal ice, ClONO{sub 2} reacts spontaneously with HCl to yield Cl{sub 2}/HONO{sub 2} in the three-water reaction and Cl{sub 2}/H{sub 3}O{sup +}-NO{sub 3}{sup {minus}} in the five-water-catalyzed reaction. Themore » calculations thus predict that the reaction of ClONO{sub 2} with HCl on PSC ice aerosols can proceed spontaneously via an ionic pathway.« less

Authors:
; ;
Publication Date:
Research Org.:
Univ. of Manchester (GB)
OSTI Identifier:
20034422
Resource Type:
Journal Article
Journal Name:
Journal of Physical Chemistry A: Molecules, Spectroscopy, Kinetics, Environment, amp General Theory
Additional Journal Information:
Journal Volume: 104; Journal Issue: 17; Other Information: PBD: 4 May 2000; Journal ID: ISSN 1089-5639
Country of Publication:
United States
Language:
English
Subject:
54 ENVIRONMENTAL SCIENCES; CHEMICAL REACTION KINETICS; ELECTRONIC STRUCTURE; STRATOSPHERE; CLOUDS; CHLORINE NITRATES; HYDROCHLORIC ACID; REACTION INTERMEDIATES

Citation Formats

McNamara, J.P., Tresadern, G., and Hillier, I.H. Exploration of the mechanism of the activation of ClONO{sub 2} by HCl in small water clusters using electronic structure methods. United States: N. p., 2000. Web. doi:10.1021/jp9932261.
McNamara, J.P., Tresadern, G., & Hillier, I.H. Exploration of the mechanism of the activation of ClONO{sub 2} by HCl in small water clusters using electronic structure methods. United States. doi:10.1021/jp9932261.
McNamara, J.P., Tresadern, G., and Hillier, I.H. Thu . "Exploration of the mechanism of the activation of ClONO{sub 2} by HCl in small water clusters using electronic structure methods". United States. doi:10.1021/jp9932261.
@article{osti_20034422,
title = {Exploration of the mechanism of the activation of ClONO{sub 2} by HCl in small water clusters using electronic structure methods},
author = {McNamara, J.P. and Tresadern, G. and Hillier, I.H.},
abstractNote = {High-level electronic structure calculations were used to study the mechanism of the reaction of ClONO{sub 2} with HCl in neutral water clusters containing one to five solvating water molecules. For the reaction between molecular HCl and ClONO{sub 2}, the barrier decreases from 42 kcal mol{sup {minus}1} (uncatalyzed) to essentially zero when catalyzed by only two water molecules, where the reaction products involve Cl{sub 2} and HONO{sub 2}. The calculations thus predict that the gas-phase reaction may be important in the stratospheric reactivation of ClONO{sub 2}. The reaction between ClONO{sub 2} and solvated H{sub 3}O{sup +}Cl{sup {minus}}, as on the polar stratospheric cloud (PSC) surface, was investigated with clusters involving up to seven water molecules. The ice-catalyzed reaction involves an ionic mechanism whereby charge transfer to ClONO{sub 2} from the attacking nucleophile leads to significant ionization along the Cl-ONO{sub 2} bond. The effect of the size of the first solvation shell of Cl{sup {minus}} is addressed by the calculations. In a cluster containing three waters and a five-water cluster structurally related to hexagonal ice, ClONO{sub 2} reacts spontaneously with HCl to yield Cl{sub 2}/HONO{sub 2} in the three-water reaction and Cl{sub 2}/H{sub 3}O{sup +}-NO{sub 3}{sup {minus}} in the five-water-catalyzed reaction. The calculations thus predict that the reaction of ClONO{sub 2} with HCl on PSC ice aerosols can proceed spontaneously via an ionic pathway.},
doi = {10.1021/jp9932261},
journal = {Journal of Physical Chemistry A: Molecules, Spectroscopy, Kinetics, Environment, amp General Theory},
issn = {1089-5639},
number = 17,
volume = 104,
place = {United States},
year = {2000},
month = {5}
}