First principles study on the structural evolution and properties of (MCl)(n) (n=1-12, M = Cu, Ag) clusters
First principles study on the structural evolution and properties of (MCl)(n) (n=1-12, M = Cu, Ag) clusters
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(MCl)(n) (n=1-12, M = Cu, Ag)团簇结构演化和性质的第一性原理研究
DOI：
10.1039/c6ra01258b
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发表时间：
2016
期刊：
影响因子：
3.9
通讯作者：
Cheng Longjiu
中科院分区：
文献类型：
--
作者：
Tian Zhimei;Cheng Longjiu
采用第一性原理全局极小化技术，即基于密度泛函几何优化（GA-DFT）的遗传算法，研究了（MCl）n（M = Cu，Ag，n = 1-12）团簇的结构演化.基准计算表明，在这项工作中使用的方法是可靠的预测不同异构体的（CuCl）6团簇的能量序列相比，高级别的耦合团簇方法。计算结果表明，（CuCl）n和（AgCl）n团簇的结构有许多相似之处.（MCl）n团簇的全局极小值在n = 5之前为平面和非平面单环结构，当n ≥ 6时为多环或链状结构.用非共价相互作用指数（NCI）研究了（AgCl）3，（CuCl）3，（CuCl）4和（CuCl）6团簇的分子内相互作用特征.分析了（CuCl）3和（AgCl）3团簇的电子和成键性质。在更高的水平上，计算了异构体的精细能量、结合能和结合能的二阶差，并将其作为团簇尺寸的函数进行了研究。已经发现了几种具有更高稳定性和对称性的有前途的尺寸。特别地，我们发现在n = 6，9和12时，簇采用了一种新的折叠方式，即管状构象，它们比相邻的簇更稳定，而且它们是芳香族的。
The structural evolution of (MCl)n (M = Cu, Ag, n = 1–12) clusters has been explored using a first principles global minimization technique, namely, a genetic algorithm from density functional theory geometry optimization (GA-DFT). Benchmark calculations indicate that the method used in this work is reliable in predicting the energetic sequences of different isomers of (CuCl)6 clusters compared to the high-level coupled cluster method. The computational results indicate that the structures of (CuCl)n and (AgCl)n clusters share many similarities. The global minima of (MCl)n clusters are planar and nonplanar monocyclic structures up to n = 5, and multi-ring or catenane structures when n ≥ 6. The characters of the intramolecular interactions of (AgCl)3, (CuCl)3, (CuCl)4 and (CuCl)6 clusters have been studied by the noncovalent interactions (NCI) index. The electronic and bonding properties of (CuCl)3 and (AgCl)3 clusters are analyzed. At a higher level, the refined energies of the isomers, the binding energies and the second difference of binding energies are calculated, and are examined as a function of the cluster size. Several promising sizes of higher stability and symmetry have been discovered. In particular, we find that the cluster adopts a new folding manner, tube conformation, at n = 6, 9 and 12, where they are more stable than the adjacent clusters; moreover, they are aromatic.