Dataset for: Molecular Modeling of Green Leaf Volatile Methyl Salicylate on Atmospheric Air/Water Interfaces.

Dataset supporting the publication dx.doi.org/10.1021/jp4029694. Molecular Modeling of Green Leaf Volatile Methyl Salicylate on Atmospheric Air/Water Interfaces. Representative GROMACS input files used in the simulations reported in this paper. We investigated the adsorption of a green leaf volatile (GLV) compound, Methyl salicylate (MeSA), on atmospheric air/water interfaces at 298 K using thermodynamic integration (TI), potential of mean force (PMF) calculations, and classical molecular dynamics (MD) simulations. Our molecular models can reproduce experimental results of the 1-octanol/water partition coefficient of MeSA. A deep free energy minimum was found for MeSA at the air/water interface, which is mainly driven by energetic interactions between MeSA and water. At the interface, the oxygenated groups in MeSA tend to point toward the water side of the interface, with the aromatic group of MeSA lying farther away from water. Increases in the concentrations of MeSA lead to reductions in the height of the peaks in the MeSA−MeSA g(r) functions, a slowing down of the dynamics of both MeSA and water at the interface, and a reduction in the interfacial surface tension. Our results indicate that MeSA has a strong thermodynamic preference to remain at the air/water interface, and thus chemical reactions with atmospheric oxidants are more likely to take place at this interface, rather than in the water phase of atmospheric water droplets or in the gas phase.

本数据集支撑论文dx.doi.org/10.1021/jp4029694，题为《大气空气/水界面上绿叶挥发物水杨酸甲酯的分子模拟》。本数据集包含本文所报道的模拟实验中使用的代表性GROMACS输入文件。本研究于298 K下，借助热力学积分（Thermodynamic Integration, TI）、平均力势（Potential of Mean Force, PMF）计算与经典分子动力学（Classical Molecular Dynamics, MD）模拟，探究了绿叶挥发物（Green Leaf Volatile, GLV）类化合物水杨酸甲酯（Methyl Salicylate, MeSA）在大气空气/水界面的吸附行为。我们所构建的分子模型能够复现水杨酸甲酯的1-辛醇/水分配系数实验结果。研究发现，水杨酸甲酯在空气/水界面处存在一个较深的自由能极小值，该现象主要由水杨酸甲酯与水分子之间的能量相互作用所主导。在界面处，水杨酸甲酯的含氧官能团倾向于朝向界面的水相一侧，而其芳香环则远离水相。随着水杨酸甲酯浓度升高，水杨酸甲酯-水杨酸甲酯径向分布函数（g(r)）的峰值高度逐渐降低，界面处水杨酸甲酯与水分子的动力学行为均出现减慢，同时界面表面张力也随之下降。研究结果表明，水杨酸甲酯在热力学上具有极强的空气/水界面驻留偏好性，因此其与大气氧化剂的化学反应更易发生于该界面处，而非大气水滴的水相或气相环境中。