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MXn(M=Al,In;X=F,CN,BH4)团簇超卤特性的理论研究

时间:2019-02-21 17:14来源:毕业论文
MX4(M=Al,In,X=F,CN,BH4)团簇的垂直剥离能及绝热电子亲和能均超过卤族元素中电子亲和能最大的Cl原子(电子亲和能为3.62eV),表明这些团簇均具有超卤特征

摘要电子亲和能(EA)是表征原子和分子反应的最重要的因素,在元素周期表中,卤素获得电子能力是最强,对应的具有最高的电子亲和能(如氯元素EA(Cl)=3.6 eV)。过去30年来,大量的研究表明如果扩展到团簇和分子范围,他们的亲和能甚至比Cl大,这部分分子被称为超卤素(superhalogen),具有通式MXn+1,其中M是金属原子,X为类卤族元素,n是金属的化合价;如果超卤素作为修饰基团,又可得到亲和能更大的飚卤素(hyperhalogen)。本文采用密度泛函理论方法,对第三主族原子Al和In元素由基团F,CN,BH4修饰组合而成的团簇MXn(M=Al,In;X=F,CN,BH4)的几何结构、电子结构(包括垂直剥离能(Vertical Detachment energy,VDE), 电子亲和能(Adiabatic Electron affinity, AEA)进行了理论计算研究,探究其中的是否具有超卤行为。对每一种尺寸的团簇,我们选取了几种可能的结构,采用Dmol3软件对其结构进行优化,得到相对的最低能结构。结果表明,Al与In的最低能结构十分相似。在结构优化的基础上,进一步计算了这些团簇的垂直剥离能(VDE)及绝热电子亲和能(AEA)。结果表明,MX4(M=Al,In,X=F,CN,BH4)团簇的垂直剥离能及绝热电子亲和能均超过卤族元素中电子亲和能最大的Cl原子(电子亲和能为3.62eV),表明这些团簇均具有超卤特征。33462
关键词: 超卤素,团簇,密度泛函理论,电子亲和能,垂直剥离能
毕业设计说明书(毕业论文外文摘要
Title:    Theoretical Study on the Superhalogens Behavior of MXn(M=Al,In,X=F,CN,BH4) Clusters

源`自*六)维[论*文'网www.lwfree.cn


Abstract
Electron affinity (EA) is one of the most important factors that govern reactivity of atoms and molecules. Chlorine, with the highest electron affinity (3.6 eV) of all elements in the periodic table, is a classic example of reactive elements. Over past thirty years, much research has been done to expand the scope of molecules with electron affinities even larger than that of Cl. These molecules, called superhalogens, have the general formul a MXn+1 where M is a metal atom, X is a halogen atom, and n is the valency of the metal. In this paper, the geometric structures and electronic character of MXn (M=Al, In; X=F, CN, BH4) clusters were calculated by density functional theory method, so as to explore the superhalogen behavior of these clusters. For each cluster size, several possible geometries were selected as the initio structures, and optimized. The calculated results indicate that, the In and Al clusters have similar lowest-energy structures, showing similar growth modes. Based on these results, we further calculated the Vertical detachment energy (VDE) and Adiabatic electron affinity (AEA) of these clusters. The results indicate that MX4 (M=Al, In; X=F, CN, BH4) clusters are superhalogen with the electron affinity (EA) that is larger than one of Cl atom (EA=3.62eV), therefore, we proposed that MX4 (M=Al, In; X=F, CN, BH4) clusters will have superhalogens behavior.
Keywords: superhalogen, cluster, density functional theory, electron affinity,vertical detachment energy
目   次
1   引言    1
2   计算方法    5
2.1 密度泛函理论的提出    5
2.2 密度泛函理论       5
2.3 Materials Studio软件简介    9
3   计算过程及结果分析    11 
3.1 MFn团簇的几何结构和电子性质    11                           源`自*六)维[论*文'网www.lwfree.cn
3.2 M(CN)n团簇结构的几何结构和电子性质    13
3.3 M(BH4)n团簇的几何结构和电子性质    16            MXn(M=Al,In;X=F,CN,BH4)团簇超卤特性的理论研究:http://www.lwfree.cn/wuli/20190221/30585.html
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