Gas-Phase Photolysis of Hg(I) Radical Species: A New Atmospheric Mercury Reduction Process

Alfonso Saiz-Lopez, A. Ulises Acuña, Tarek Trabelsi, Javier Carmona-García, Juan Z. Dávalos, Daniel Rivero, Carlos A. Cuevas, Douglas E. Kinnison, Sebastian P. Sitkiewicz, Daniel Roca-Sanjuán, Joseph S. Francisco

Research output: Contribution to journalArticlepeer-review

53 Scopus citations

Abstract

The efficient gas-phase photoreduction of Hg(II) has recently been shown to change mercury cycling significantly in the atmosphere and its deposition to the Earth's surface. However, the photolysis of key Hg(I) species within that cycle is currently not considered. Here we present ultraviolet-visible absorption spectra and cross-sections of HgCl, HgBr, HgI, and HgOH radicals, computed by high-level quantum-chemical methods, and show for the first time that gas-phase Hg(I) photoreduction can occur at time scales that eventually would influence the mercury chemistry in the atmosphere. These results provide new fundamental understanding of the photobehavior of Hg(I) radicals and show that the photolysis of HgBr increases atmospheric mercury lifetime, contributing to its global distribution in a significant way.

Original languageEnglish
Pages (from-to)8698-8702
Number of pages5
JournalJournal of the American Chemical Society
Volume141
Issue number22
DOIs
StatePublished - Jun 5 2019

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