Hydration of acetic acid-dimethylamine complex and its atmospheric implications
Hydration of acetic acid-dimethylamine complex and its atmospheric implications
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乙酸-二甲胺络合物的水合及其大气影响
DOI：
10.1016/j.atmosenv.2019.117005
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发表时间：
2019
影响因子：
5
通讯作者：
Huang Wei
中科院分区：
文献类型：
--
作者：
Li Jie;Feng Ya-Juan;Jiang Shuai;Wang Chun-Yu;Han Ya-Juan;Xu Cai-Xin;Wen Hui;Huang Teng;Liu Yi-Rong;Huang Wei
大气气溶胶与天气、气候和人类健康密切相关，而新粒子形成（NPF）是大气气溶胶的主要来源。目前，一些野外观测和实验表明，乙酸（HOAc）可能参与NPF事件。然而，醋酸成核的机理还不清楚。本文在PW 91/PW 91/6-311++G（3df，3 pd）水平上对乙酸（HOAc）-二甲胺（DMA）-水（W）体系的基态结构和热力学进行了研究。发现乙酸与二甲胺形成了相对稳定的团簇，质子转移增强了（HOAc）（DMA）（H2O）n（n = 2-4）团簇中氢键的强度.温度对异构体的分布有重要影响，特别是对（HOAc）（DMA）（H2O）2团簇。此外，所有的异构体都有助于团簇的成核。不同的相对湿度对水合物分布的影响可以忽略不计。然而，从水合物分布和团簇形成速率的比较中可以看出，未水合团簇总是占主导地位的，它们更容易形成稳定的团簇。上述分析表明（HOAc）（DMA）是相对稳定的，并且基于（HOAc）（DMA）的一些较大的簇可能参与新颗粒的形成。
Atmospheric aerosols are closely related to weather, climate and human health, and New particle formation (NPF) is a major source of atmospheric aerosols. Currently, some field observations and experiments indicate that acetic acid (HOAc) could be involved in NPF events. However, mechanism of acetic acid nucleation is still unclear. In this study, the low-lying structures and thermodynamics of acetic acid (HOAc)-dimethylamine (DMA)-water (W) system were studied at PW91PW91/6–311++G (3df, 3pd) level. We found that acetic acid forms relatively stable clusters with dimethylamine, and that proton transfer enhances the strength of the hydrogen bond in (HOAc) (DMA) (H2O)n(n = 2–4) clusters. Temperature has an important effect on the distribution of isomers, especially for (HOAc) (DMA) (H2O)2clusters. Besides, all the isomers contribute to the nucleation of clusters. The various RH has a negligible effect on the hydrate distribution. However, the non-hydrated clusters are always dominant and they are easy to form stable cluster, as seen from the comparison of hydrate distributions and cluster formation rates. The above analyses indicate that (HOAc) (DMA) is relatively stable and some larger clusters based on (HOAc) (DMA) may participate in new particle formation.