Stabilization mechanism of Si 12 cage clusters by encapsulation of a transition-metal atom: A density-functional theory study
Stabilization mechanism of Si 12 cage clusters by encapsulation of a transition-metal atom: A density-functional theory study
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DOI：
10.1103/physrevb.74.205427
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发表时间：
2006-11
影响因子：
3.7
通讯作者：
N. Uchida;T. Miyazaki;T. Kanayama
中科院分区：
文献类型：
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作者：
N. Uchida;T. Miyazaki;T. Kanayama
我们系统地研究了过渡金属封装笼状团簇（,Ta， W, Re, Os, Ir， Pt和Au）的几何和电子结构，主要关注它们出色的稳定性，使用基于密度泛函理论的计算。我们发现，除了团簇属于两种不同的结构类别，对称六角形棱柱（HP；为W， Re和Os，每个团簇的总价电子数，范围从53到56）和不对称的四五角形面（FPF;=Re, Os, Ir， Pt和Au，范围从55到59）结构。HP结构特别稳定，这是根据18电子规则的电子壳封闭来理解的，并且在，55和56中，通过与Si笼之间的共价键以及笼到电荷的转移来保持几何对称。FPF结构的能量最低，并由相同的共价键/电荷转移机制维持其他值。我们认为所有这些结果都源于HP和FPF Si保持架的电子“刚度”对变化的影响，这是控制稳定性的主要因素。
We systematically studied the geometrical and electronic structures of transition-metal-encapsulatingcage clusters,(, Ta, W, Re, Os, Ir, Pt, and Au), mainly focusing on their outstanding stability, using calculations based on density-functional theory. We found that theclusters exceptbelong to either of two distinct structural classes, the-symmetric hexagonal prism (HP; for, W, Re, and Os; total number of valence electrons per cluster,, ranging from 53 to 56) and less-symmetric four pentagonal face (FPF;=Re, Os, Ir, Pt, and Au;ranging from 55 to 59) structures. The HP structure is particularly stabilized at, which is understood in terms of the electronic shell closure of theatoms due to the 18-electron rule, and the geometrical symmetry is maintained for, 55, and 56 by the covalent bonding between theatom and the Si cage accompanied by the cage-to-charge transfer. The FPF structure is lowest in energy forand is maintained by the same covalent-bond/charge-transfer mechanism for other values of. We propose that all these results originate from the electronic “rigidness” of the HP and FPF Si cages against the variation of, which is the leading factor governing the stability of.