2-甲基甘油酸-水团簇的大气物化特性研究  

Study on Atmospheric Physicochemical Characterization of 2-Methylglyceric Acid-Water Clusters

作　　者：赵锋 ZHAO Feng(College of General Education and Foreign Languages,Anhui Institute of Information Technology,Wuhu 241000,China;Science Island Branch,Graduate School,University of Science and Technology of China,Hefei 230026,China)

机构地区：[1]安徽信息工程学院通识教育与外国语学院,安徽芜湖241000 [2]中国科学技术大学研究生院科学岛分院,安徽合肥230026

出　　处：《新乡学院学报》2024年第6期19-22,共4页Journal of Xinxiang University

基　　金：安徽省高校自然科学研究项目(KJ2020A0821,KJ2020A0820)。

摘　　要：新粒子生成是大气气溶胶的主要来源,而临界核的形成是新粒子生成的起点。2-甲基甘油酸(MGA)和水(H2O)作为潜在的成核前体物,可能对大气新粒子生成有贡献。因此,基于密度泛函理论(DFT)探究了MGA-H2O团簇的几何结构、热力学性质和异构体相对占比。结果表明:(MGA)(H2O)n(n=1~4)团簇都具有稳定的结构,但只有(MGA)(H2O)2和(MGA)(H2O)3团簇的形成可以自发进行。预测了大气中(MGA)(H2O)2和(MGA)(H2O)3团簇异构体相对占比的温度依赖性;低温时(MGA)(H2O)2和(MGA)(H2O)3团簇的最稳定结构(全局最小值)占据主导地位;随着温度升高,其他低能量异构体的占比迅速增加。此外,H2O更倾向于以团簇(H2O)n的形式与MGA结合。总的来说,MGA-H2O体系能够以二水合物(MGA)(H2O)2和三水合物(MGA)(H2O)3的形式为大气新粒子生成作出贡献。New particle formation is a major source of atmospheric aerosols,and critical nucleation is the starting point.Cur-rently,information on nucleation species and mechanisms at the molecular level is incomplete.2-Methylglycerol acid(MGA)and water(H2O),as potential nucleation precursors,may contribute to atmospheric new particle formation.Therefore,the geometrical structure,thermodynamic properties,and relative occupancy of isomers of MGA-H2O clusters were explored based on density-functional theory(DFT).The results show:(MGA)(H2O)n(n=1~4)clusters all have stable structures,but only the formation of(MGA)(H2O)2 and(MGA)(H2O)3 clusters can proceed spontaneously,thus predicting the temperature dependence of the relative proportion of isomers in(MGA)(H2O)2 and(MGA)(H2O)3 cluster isomers in the atmosphere;the most stable structures(global minimum)of(MGA)(H2O)2 and(MGA)(H2O)3 clusters dominate at low temperatures;the percentages of other low-energy isomers increase rapidly with increasing temperature.In addition,H2O prefers to bind to MGA in the form of cluster(H2O)n.Overall,the MGA-H2O system is able to contribute to atmospheric new particle formation in the form of dihy-drate(MGA)(H2O)2 and trihydrate(MGA)(H2O)3.

关 键 词：大气气溶胶 团簇 新粒子生成 密度泛函理论 

分 类 号：O641[理学—物理化学] X131.1[理学—化学]