密度泛函理论研究MgnOn(n=2—8)团簇的结构和电子性质

采用密度泛函理论中的广义梯度近似对MgnOn(n=2-8)团簇的几何构型进行优化,并对能量、频率和电子性质进行了计算.结果表明,当n=2,3时,团簇的最低能量结构是平面结构;当n≥4时.团簇的最低能量结构可以看成是由Mg2O2和Mg3O3单元组成的三维结构.O-Mg-O的钝角和较多的电荷转移对团簇的稳定性起着重要的作用.随着团簇尺寸的增大,转移的电荷逐渐增加,转移的电荷量有达到块体中电荷值的趋势.团簇的垂直电离势、亲和势和最高已占据轨道与最低未占据轨道的能隙表明,Mg3O3和Mg6O6是稳定的团簇.     

Density-functional investigation of 3d,4d,5d impurity doped Au6 clusters

The general features of the geometries and electronic properties for 3d,4d,and 5d transition-metal atom doped Au 6 clusters are systematically investigated by using relativistic all-electron density functional theory in the generalized gradient approximation(GGA).A number of structural isomers are considered to search the lowest-energy structures of M@Au 6 clusters(M=3d,4d and 5d transition-metal atoms),and the transition metal atom locating in the centre of an Au 6 ring is found to be in the ground state for all the M@Au 6 clusters.All doped clusters,expect for Pd@Au 6,show large relative binding energies compared with a pure Au 7 cluster,indicating that doping by 3d,4d,5d transition-metal atoms could stabilize the Au 6 ring and promote the formation of a new binary alloy cluster.     

High stability of the goldalloy fullerenes：A density functional theory investigation of M_（12）@Au_（20）（M=Na,Al,Ag,Sc,Y,La,Lu,and Au） clusters

Discovering highly stable metal fullerenes such as the celebrated C 60 is interesting in cluster science as they have potential applications as building blocks in new nanostructures.We here investigated the structural and electronic properties of the fullerenes M 12 @Au 20（M=Na,Al,Ag,Sc,Y,La,Lu,and Au）,using a first-principles investigation with the density functional theory.It is found that these compound clusters possess a similar cage structure to the icosahedral Au 32 fullerene.La 12 @Au 20 is found to be particularly stable among these clusters.The binding energy of La 12 @Au 20 is 3.43 eV per atom,1.05 eV larger than that in Au 32.The highest occupied molecular orbital-lowest unoccupied molecular orbital（HOMO-LUMO） gap of La 12 @Au 20 is only 0.31 eV,suggesting that it should be relatively chemically reactive.     

第一性原理计算MgBeN（N=1～7）团簇的最低能量结构及其电子性质

本文从第一性原理出发，利用密度泛函理论（DFT）计算了MgBeN（N=1—7）团簇的最低能量结构及其电子性质．计算结果表明，MgBeN（N=1—7）团簇最低能量结构的对称性与单一组分的镀团簇相比有所降低，Mg-Be最近邻原子间距和能隙随团簇尺寸的增加出现了振荡现象，从结构稳定性上来看。N=3是MgBeN（N=1—7）团簇的一个幻数。     

第一性原理对NaBen(n=1—12)团簇最低能量结构及其电子性质的研究

从第一性原理出发对NaBe_n(n=1—12)团簇的最低能量结构和电子性质进行了研究.结果表明，掺杂原子(Na)导致主团簇Be_n的几何结构发生显著变化；出现了共价键和金属键的成键特性；Na-Be最近邻间距和能隙随着团簇尺寸的增加出现了振荡;n=4是团簇的幻数. 关键词： n团簇')" href="#">NaBe_n团簇 最低能量结构 电子性质     

关于氦团簇离子He^＋4的离解能和相对稳定结构

本文应用排列通道量子力学方法，对氦团族离子Ｈｅ＾＋４的四种可能构型进行了研究，发现Ｈｅ＾＋４的相对稳定结构为“Ｔ”形构型，对应Ｈｅ＾＋４→Ｈｅ＾＋３＋Ｈｅ的离解能为０．４２ｋｃａｌ／ｍｏｎ。该结果同其它作者的ａｂ ｉｎｉｔｉｏ结果相吻合。     

利用密度泛函理论研究BnNi(n≤5)小团簇的结构和磁性

基于第一性原理，用密度泛函理论中的广义梯度近似方法，获得了B_nNi(n≤5)小团簇在不同自旋多重度下的几何构型，确定了最低能量结构，并计算了相应的频率、平均结合能和磁性. 结果表明：B_nNi(n≤5)小团簇最低能量结构的自旋多重度分别为2，1，2，1，2；Ni掺入B团簇后增大了其结合能；Ni原子磁矩和团簇总磁矩随团簇尺寸增大而呈现振荡趋势. 关键词： nNi小团簇')" href="#">B_nNi小团簇 自旋多重度 磁性     

Density functional study of Al-doped Au clusters

The equilibrium geometries and electronic properties of Au_nAl, up to n=13, have been systematically investigated using the density functional theory. The results show that, for the Au_nAl clusters, two patterns are identified. Pattern one (n=2, 3, 8), the lowest-energy geometries prefer two-dimensional structures. Pattern two (n=4-7, 9--13), the lowest-energy geometries prefer three-dimensional structures. According to the analysis of the binding energy and the fragmentation energy, Au_nAl clusters with odd n are found to be more stable than those with even n. The same trend of alternation can be illuminated according to the computational results in the HOMO--LUMO gap, the ionization potential, and the electron affinities. The Al atom not only changes the structures of pure gold clusters, but also enhances their stabilities. NBO analysis indicates 6s orbital of Au atom hybridizes with 3p orbital of Al atom.     

Appearance of metallic features in small tungsten clusters

The structures and properties of W_n (n=2--14) clusters were studied by using the density functional theory (DFT) at LSDA level. The most stable structures of W_n (n=2--14) clusters with global minimum were determined. The average binding energy (E_b), the first and second difference of total energy (\itδ E, \itδ₂E), the vertical detachment energy (VDE), and the HOMO-LUMO gap versus the size were also discussed. The abrupt decrease of VDE and HOMO-LUMO gap at size n=8 and 10 implied that tungsten clusters of W₈ and W₁₀ appeared to have metallic features. These changes were also accompanied by the delocalization of electron charge density and the strong hybridization between 5d and 6s orbits in W₈ and W_10 clusters. Our results are in good agreement with the available experimental data.     

碱土金属吸附二维α_1硼烯结构和性质研究

采用密度泛函理论系统计算和研究了碱土金属(铍、镁和钙)单原子、二聚体、双原子吸附新型二维α_1硼烯后众多可能的吸附点和吸附情况.通过体系总能量的计算,鉴定了不同吸附体系最稳定的几何构型,并对其稳定性进行了详细地分析和讨论.经研究发现单原子铍和镁最低吸附点是空心位,而钙是顶位附近.通过吸附能计算发现二聚体碱土金属吸附硼烯后体系的稳定性高于单原子情况,但低于双原子吸附,表明碱土金属原子倾向于孤立地吸附于各自最低能量吸附点,而不是以团簇形式吸附.通过电荷转移和态密度进一步分析和讨论了碱土金属原子与硼烯的相互作用和成键方式,发现碱土金属与硼烯之间同时具有离子键和共价键性质.