全金属负离子团簇Ga_4^(2-)、In_4^(2-)_芳香性的磁特征与多重芳香性  

Magnetic Characteristics for Aromaticity and Multiple-fold Aromaticity in All-metal Dianionic Clusters Ga_4^(2-) and In_4^(2-)

作　　者：池贤兴[1] 徐小秋[1] 陈向军[2] 苑震生[2] 

机构地区：[1]温州师范学院物理与电子信息学院,温州325027 [2]合肥微尺度物质科学国家实验室

出　　处：《Chinese Journal of Chemical Physics》2005年第6期941-946,共6页化学物理学报（英文）

基　　金：ProjectsupportedbyZhejiangProvincialNaturalScienceFoundationofChina(102069).

摘　　要：运用密度泛函理论的两种方法(B3LYP、B3PW91)与二级微扰方法(MP2),对二价负离子全金属团簇Ga42-、In42-的稳定结构、振动频率与电子总能量作了计算.在此基础上,运用B3LYP与HF两种方法,着重对最稳定的正方形结构的Ga42-、In42-团簇的两种磁性质:各向异性磁化率与核独立化学位移进行了研究.计算结果表明,正方形结构Ga42-、In42-团簇具有很强的芳香性.接着对它们进行细致的分子轨道结构分析,揭示了正方形结构Ga42-、In42-团簇具有多重芳香性,一个非局域π分子轨道与两个非局域σ分子轨道对此两种金属团簇的芳香性都起了重要作用.The optimized geometries, frequencies, and total electronic energies of two all-metal dianionie clusters Ga4^2-、In4^2- are calculated at the B3LYP, B3PW91, and MP2 levels of theory. There are two stable structures for each Ga4^2-、In4^2- species. For Ga4^2-、In4^2- species the square isomers are the most stable. On the basis of these computed stable structures we focus on two magnetic properties： magnetic susceptibility anisotropy and nucleus- independent chemical shift （NICS） for the square planar Ga4^2-、In4^2-isomers, which are calculated with B3LYP and HF methods. The computed results of NICS show that the square planar Ga4^2-、In4^2-isomers possess strong aromatieity, The detailed molecular orbital analysis for the two isomers further reveals that the two square planar Ga4^2-、In4^2- isomers have multiple-fold aromatieity： one delocalized π MOs and two delocalized σ MOs, which play important role in exolaininz the soecial stability of these all-metal square clusters.

关 键 词：金属团簇 芳香性 磁性质 多重芳香性 

分 类 号：O641.4[理学—物理化学]