Institute of Intelligent Machines, Chinese Academy of Sciences, Hefei, 230031, AnHui, PR China.
J Phys Chem A. 2008 May 22;112(20):4562-7. doi: 10.1021/jp801828b.
The size-selective Zr(2)Si(n) (n = 16-24) caged clusters have been investigated by density functional approach in detail. Their geometries, relative stabilities, electronic properties and ionization potentials have been discussed. The dominant structures of bimetallic Zr(2) doped silicon caged clusters gradually transform to Zr(2) totally encapsulated structures with increase of the clustered size from 16 to 24, which is good agreement with the recent experimental result (J. Phys. Chem. A. 2007, 111, 42). Two novel isomers, i.e., naphthalene-like and dodecahedral Zr(2)Si(20) clusters, are found as low-lying conformers. Furthermore, the novel quasi-1D naphthalene-like Zr(n)Si(m) nanotubes are first reported. The second-order energy differences reveal that magic numbers of the different sized neutral Zr(2)Si(n) clusters appear at n = 18, 20 and 22, which are attributed to the fullerene-like, dodecahedral and polyhedral structures, respectively. The HOMO-LUMO gaps (>1 eV) of all the size-selective Zr(2)Si(n) clusters suggest that encapsulation of the bimetallic zirconium atoms is favorable for increasing the stabilities of silicon cages.
采用密度泛函方法详细研究了尺寸选择性的 Zr(2)Si(n)（n=16-24）笼状簇。讨论了它们的几何形状、相对稳定性、电子性质和电离势。随着簇尺寸从 16 增加到 24，双金属 Zr(2)掺杂硅笼状簇的主要结构逐渐转变为 Zr(2)完全包裹的结构，这与最近的实验结果（J. Phys. Chem. A. 2007, 111, 42）很好地一致。发现了两种新型的异构体，即萘状和十二面体 Zr(2)Si(20)簇，它们是低能构象。此外，首次报道了新型准一维萘状 Zr(n)Si(m)纳米管。二阶能量差表明，不同尺寸中性 Zr(2)Si(n)簇的幻数出现在 n=18、20 和 22，这分别归因于类富勒烯、十二面体和多面体结构。所有尺寸选择性 Zr(2)Si(n)簇的 HOMO-LUMO 能隙（>1 eV）表明，双金属锆原子的封装有利于增加硅笼的稳定性。
