Na_mSi_(7-m)(m≤6)团簇的结构和电子性质的密度泛函理论研究  

Equilibrium geometries and electronic properties of Na_mSi_(7-m)(m≤6) clusters with density functional theory

作　　者：刘霞[1] 赵高峰[1] 郭令举[1] 王献伟[1] 葛桂贤[1] 闫玉丽[1] 罗有华[1] 

机构地区：[1]河南大学物理与电子学院,开封475004

出　　处：《原子与分子物理学报》2007年第6期1216-1222,共7页Journal of Atomic and Molecular Physics

基　　金：国家自然科学基金(10174086)

摘　　要：采用密度泛函理论(DFT)在B3LYP/6-311+G(d)水平上,对NamSi7-m(m≤6)团簇的最低能量结构和电子性质进行了研究.结果表明:m≤4时,团簇的稳定结构倾向于Na原子附着在带负电的Si7-m结构的不同位置上,Na原子成分较多时(m≥4)混合团簇的稳定几何结构发生较大的变化,且团簇中Nam的结构与单一的Nam团簇的稳定结构不同;自然电荷布居分析表明,电荷从Na原子转移到Si原子;随着Na原子成分的增加,团簇越来越容易失去电子,且团簇的稳定性也随之减弱;随着m的增加能隙出现振荡,其中Na5Si2的能隙最小,化学活性最强,Na2Si5的能隙最大,化学活性最弱.The equilibrium geometries and electronic properties of Nam NamSi7-m（m≤6） clusters have been studied by using density functional theory at the B3LYP/6-311 ＋ G（d） level. The results indicate that the lowest energy isomer tend toward adsorption geometries where Na atoms are attached to a NamSi7-m（m≤4） framework with pronounced negative charge, It is also seen that the geometries of Na-rich clusters are significantly changes and the arrangement of Na atoms is different from that of Nam（m≥4）. According to the Natural Charge population analysis , Charges transfer from Na to Si atoms. With increasing number of Na atoms, NamSi7-m dusters tend losing electrons and their stabilities get weaker. Furthermore, the calculated highest occupied molecular orbital and lowest unoccupied molecular orbital （HOMO-LUMO） gaps of the most stable NamSi7- m clusters oscillate with increasing size of m while the gap of the NasSi2 is the lowest reflecting highest reactivity and that of the Na2Si5 is the vice versa.

关 键 词：NamSi7-m(m≤6)团簇 密度泛函理论 结构与性质 

分 类 号：O641[理学—物理化学]