Dataset for: Molecular simulations of green leaf volatiles and atmospheric oxidants on air/water interfaces

Dataset supporting the publication dx.doi.org/10.1039/C3CP44090G. Molecular simulations of green leaf volatiles and atmospheric oxidants on air/water interfaces. Representative GROMACS input files used in the simulations reported in this paper. 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.

本数据集为论文dx.doi.org/10.1039/C3CP44090G的发表提供支撑。本研究针对空气/水界面上的绿叶挥发性有机物与大气氧化剂开展分子模拟，同时提供了本文报道的模拟工作中使用的代表性GROMACS输入文件。绿叶挥发性有机物（Green Leaf Volatiles, GLVs）是植物释放的含氧烃类物质，尤其在机械损伤、局地天气变化等胁迫条件下释放量显著提升。GLVs可与大气水滴中光化学生成的氧化剂（如羟基自由基（OH radicals））发生反应，助力二次有机气溶胶（Secondary Organic Aerosols, SOAs）的形成。本研究采用经典分子动力学（Molecular Dynamics, MD）模拟与平均力势（Potential of Mean Force, PMF）计算，探究了气相绿叶挥发性有机物2-甲基-3-丁烯-2-醇（2-methyl-3-buten-2-ol, MBO）与羟基自由基在大气空气/水界面的吸附行为。本研究构建的模型能够复现实验测得的MBO与羟基自由基的水合自由能数值，以及本研究实验测定的MBO的1-辛醇/水分配系数。MBO与羟基自由基均存在强烈的热力学驱动力以停留在空气/水界面，二者的密度分布在界面处发生显著重叠。上述结果表明，MBO与羟基自由基之间的化学反应更易发生在界面处，而非水滴本体或气相环境中。模拟中观测到MBO与羟基自由基存在大量接触，这暗示二者之间可发生反应。