title: Molecular simulations of green leaf volatiles and atmospheric oxidants on air/water interfaces.
abstract: Green leaf volatiles (GLVs) are oxygenated hydrocarbons that are emitted by plants, especially under stress conditions such as mechanical damage and local weather changes. GLVs can react with photochemically-generated oxidants (e.g., OH radicals) in atmospheric water drops, and contribute to the formation of secondary organic aerosols (SOAs). Here we investigated the adsorption of a gas phase GLV, 2-methyl-3-buten-2-ol (MBO) and OH radicals on atmospheric air/water interfaces using classical molecular dynamics (MD) simulations and potential of mean force (PMF) calculations. Our models can reproduce experimental values of the free energy of hydration of MBO and ˙OH, as well as 1-octanol/water partition coefficients of MBO determined experimentally in this study. Both MBO and ˙OH have a strong thermodynamic incentive to remain at the air/water interface, with their density profiles overlapping significantly at the interface. These results suggest that chemical reactions between MBO and ˙OH are more likely to take place at the interface, rather than inside the bulk of water droplets or in the vapor phase. We found a significant number of contacts between MBO and ˙OH in our simulations, which could lead to reactions between these two species.
authors: Cain Department of Chemical Engineering, Louisiana State University, Baton Rouge, LA 70803, USA.
authors: Thilanga P
authors: TP
authors: Liyana-Arachchi
authors: Christopher
authors: C
authors: Stevens
authors: Amie K
authors: AK
authors: Hansel
authors: Franz S
authors: FS
authors: Ehrenhauser
authors: Kalliat T
authors: KT
authors: Valsaraj
authors: Francisco R
authors: FR
authors: Hung