Acta Chimica Sinica ›› 2021, Vol. 79 ›› Issue (8): 1065-1072.DOI: 10.6023/A21040147 Previous Articles     Next Articles

Article

一种量子化学组合方法及其应用于汞对硫酸气溶胶形成影响的研究

李程桥, 王一波*()   

  1. 贵州大学化学与化工学院 贵州省高性能计算化学重点实验室 贵阳 550025
  • 投稿日期:2021-04-12 发布日期:2021-06-01
  • 通讯作者: 王一波
  • 基金资助:
    国家自然科学基金(21767005); 贵州省科技计划项目(20175788)

A Combination Method of Quantum Chemistry and Its Application to the Study of the Effects of Mercury on the Formation of Sulfuric Acid Aerosol

Chengqiao Li, Yibo Wang()   

  1. School of Chemistry and Chemical Engineering, Guizhou University, Key Laboratory of High Performance Computational Chemistry, Guiyang 550025, China
  • Received:2021-04-12 Published:2021-06-01
  • Contact: Yibo Wang
  • Supported by:
    National Natural Science Foundation of China(21767005); Science and Technology Plan Project of Guizhou Province(20175788)

Haze weather has been occurring frequently in recent years, and studies have shown that its formation mechanism is related to the nucleation of sulfuric acid aerosols. How mercury and its compounds affect the formation and growth of sulfuric acid aerosols is completely unclear in polluted areas where sulfur and mercury coexist. In order to explore this problem theoretically, we established a new quantum chemistry combination method. Millions of cluster structures are generated by using the Molclus Genmer module. The cluster geometries are preliminarily optimized by the GFN2-xTB method and sorted according to the Gibbs free energy changes of the cluster generation process. The top 100 optimized structures were re-optimized using the B3PW91-D3(BJ) method. In order to accurately calculate the binding energy of clusters, we established a small benchmark set based on the composition and structural characteristics of the clusters studied in the project, and used the CCSD(T)/CBS method to calculate the binding energy of each cluster model in the benchmark set. Using the binding energy as a standard, the best method selected from 42 DFT methods is ωB97M-D3(BJ). The binding energy calculated by B3PW91-D3(BJ) is corrected by the results of the ωB97M-D3(BJ) method to obtain an accurate thermodynamic function value. It is worth mentioning that the combined method was used to study a total of 2.4 million structures in 8 cluster models formed by mercury and its typical compounds, sulfuric acid and water. The results show that polar compounds of mercury such as HgSO4 and HgO, together with Hg22+ and Hg2+, can promote sulfuric acid aerosol formation, while Hg and non-polar HgCl2 and Hg2Cl2 have almost no effect on the nucleation of sulfuric acid aerosol. In addition, we found that the conclusion holds true for the temperature interval of the troposphere at standard atmospheric pressure. This conclusion provides valuable predictions for the studies on sulfuric acid aerosol nucleation mechanisms under the combined sulfur and mercury pollution environment.

Key words: quantum chemistry, combination method, sulfuric acid aerosols, mercury, thermodynamic function