Theoretical study of the hydration of atmospheric nucleation precursors with acetic acid.
Theoretical study of the hydration of atmospheric nucleation precursors with acetic acid.
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DOI：
10.1021/jp506226z
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发表时间：
2014-08
期刊：
影响因子：
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通讯作者：
Yu-Peng Zhu;Yirong Liu;Teng Huang;Shuai Jiang;Kang-Ming Xu;Hui Wen;Wei-Jun Zhang;Wei Huang
中科院分区：
文献类型：
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作者：
Yu-Peng Zhu;Yirong Liu;Teng Huang;Shuai Jiang;Kang-Ming Xu;Hui Wen;Wei-Jun Zhang;Wei Huang
虽然已知大气中含有很大一部分有机物质，并且发现乙酸稳定水合硫酸的效果与氨接近，但人们对 (CH3COOH)(H2SO4)2 水合的细节知之甚少，特别是对于具有更多水分子的较大簇。我们利用密度泛函理论 (DFT) 在 PW91PW91/6-311++G(3df,3pd) 水平上研究了水合物的结构特征和热力学。结构演化现象可能存在于团簇形成的早期阶段，我们初步提出了一种通过结构演化来计算团簇形成吉布斯自由能的路径。这项研究的结果提供了由两个硫酸分子、一个乙酸分子和最多三个水组成的系统中硫酸首次去质子化的图片，分别在 0 和 298.15 K 下。我们还用 (CH3COOH)(H2SO4)2 中的硫酸氢根阴离子替换其中一种硫酸，以探讨两个系列团簇之间酸解离的差异以及离子介导成核和有机物增强成核之间团簇生长性能的相互作用。
While atmosphere is known to contain a significant fraction of organic substance and the effect of acetic acid to stabilize hydrated sulfuric acids is found to be close that of ammonia, the details about the hydration of (CH3COOH)(H2SO4)2 are poorly understood, especially for the larger clusters with more water molecules. We have investigated structural characteristics and thermodynamics of the hydrates using density functional theory (DFT) at PW91PW91/6-311++G(3df,3pd) level. The phenomena of the structural evolution may exist during the early stage of the clusters formation, and we tentatively proposed a calculation path for the Gibbs free energies of the clusters formation via the structural evolution. The results in this study supply a picture of the first deprotonation of sulfuric acids for a system consisting of two sulfuric acid molecules, an acetic acid molecule, and up to three waters at 0 and 298.15 K, respectively. We also replace one of the sulfuric acids with a bisulfate anion in (CH3COOH)(H2SO4)2 to explore the difference of acid dissociation between two series of clusters and interaction of performance in clusters growth between ion-mediated nucleation and organics-enhanced nucleation.