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Title: Atmospheric Chemistry of HOHg (II) O • Mimics That of a Hydroxyl Radical
HOHg(II)O•, formed from HOHg(I)• + O3, is a key intermediate in OH-initiated oxidation of Hg(0) in the atmosphere. As no experimental data is available for HOHg(II)O•, we use computational chemistry (CCSD(T)//M06-2X/AVTZ) to characterize its reactions with atmospheric trace gases (NO, NO2, CH4, C2H4, CH2O and CO). In summary, HOHg(II)O•, like the analogous BrHg(II)O• radical, largely mimics the reactivity of •OH in reactions with NOx, alkanes, alkenes, and aldehydes. The rate constant for its reaction with methane (HOHg(II)O• + CH4 → Hg(II)(OH)2 + •CH3) is about four times higher than that of •OH at 298 K. All these reactions maintain mercury as Hg(II), except for HOHg(II)O• + CO → HOHg(I)• + CO2. Considering only the six reactions studied here, we find that reduction by CO dominates the fate of HOHg(II)O• (79-93%) in many air masses (in the stratosphere and at ground level in rural, marine, and polluted urban regions) with only modest competition from HOHg(II)O• + CH4 (<15%). We expect that this work will help global modeling of atmospheric mercury chemistry.  more » « less
Award ID(s):
2004100
PAR ID:
10552421
Author(s) / Creator(s):
; ; ;
Publisher / Repository:
American Chemical Society
Date Published:
Journal Name:
The Journal of Physical Chemistry A
Volume:
127
Issue:
40
ISSN:
1089-5639
Page Range / eLocation ID:
8392 to 8403
Subject(s) / Keyword(s):
Mercury atmospheric chemistry computational chemistry kinetics radicals
Format(s):
Medium: X
Sponsoring Org:
National Science Foundation
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