title: Computational study of the effect of glyoxal-sulfate clustering on the Henry's law coefficient of glyoxal.
abstract: We have used quantum chemical methods to investigate the molecular mechanism behind the recently reported ( Kampf , C. J. ; Environ. Sci. Technol . 2013 , 47 , 4236 - 4244 ) strong dependence of the Henry's law coefficient of glyoxal (C2O2H2) on the sulfate concentration of the aqueous phase. Although the glyoxal molecule interacts only weakly with sulfate, its hydrated forms (C2O3H4 and C2O4H6) form strong complexes with sulfate, displacing water molecules from the solvation shell and increasing the uptake of glyoxal into sulfate-containing aqueous solutions, including sulfate-containing aerosol particles. This promotes the participation of glyoxal in reactions leading to secondary organic aerosol formation, especially in regions with high sulfate concentrations. We used our computed equilibrium constants for the complexation reactions to assess the magnitude of the Henry's law coefficient enhancement and found it to be in reasonable agreement with experimental results. This indicates that the complexation of glyoxal hydrates with sulfate can explain the observed uptake enhancement.
authors.affiliation: †Department of Chemistry, University of Helsinki, P.O. Box 55, FI-00014 Helsinki, Finland.
authors.forename: Theo
authors.initials: T
authors.lastname: Kurtén
authors.affiliation: ‡Department of Chemistry, University of Copenhagen, Universitetsparken 5, 2100 Kobenhavn Ø, Denmark.
authors.forename: Jonas
authors.initials: J
authors.lastname: Elm
authors.affiliation: §Department of Physics, University of Helsinki, P.O. Box 64, FI-00014 Helsinki, Finland.
authors.forename: Nønne L
authors.initials: NL
authors.lastname: Prisle
authors.affiliation: ‡Department of Chemistry, University of Copenhagen, Universitetsparken 5, 2100 Kobenhavn Ø, Denmark.
authors.forename: Kurt V
authors.initials: KV
authors.lastname: Mikkelsen
authors.affiliation: ∥Institute for Inorganic and Analytical Chemistry, Johannes Gutenberg University, Duesbergweg 10-14, 55128 Mainz, Germany.
authors.forename: Christopher J
authors.initials: CJ
authors.lastname: Kampf
authors.affiliation: ⊥Cooperative Institute for Research in Environmental Sciences (CIRES), 216 UCB, University of Colorado at Boulder, Boulder, Colorado 80309-0216, United States.|#Department of Chemistry and Biochemistry, 215 UCB, University of Colorado at Boulder Boulder, Colorado 80309-0215, United States.
authors.forename: Eleanor M
authors.initials: EM
authors.lastname: Waxman
authors.affiliation: ⊥Cooperative Institute for Research in Environmental Sciences (CIRES), 216 UCB, University of Colorado at Boulder, Boulder, Colorado 80309-0216, United States.|#Department of Chemistry and Biochemistry, 215 UCB, University of Colorado at Boulder Boulder, Colorado 80309-0215, United States.
authors.forename: Rainer
authors.initials: R
authors.lastname: Volkamer
mesh_terms: D000336:Aerosols / Q000737:chemistry; D001272:Atmosphere / Q000737:chemistry; D003198:Computer Simulation; D006037:Glyoxal / Q000737:chemistry*; D008956:Models, Chemical; D011312:Pressure; D012997:Solvents / Q000737:chemistry; D013431:Sulfates / Q000737:chemistry*; D014867:Water / Q000737:chemistry
chemical_list: D000336:Aerosols; D012997:Solvents; D013431:Sulfates; D014867:Water; D006037:Glyoxal