银原子簇的紧束缚分子动力学研究
Tight-binding molecular dynamic study of silver clusters
摘要：
采用紧束缚分子动力学（TBMD）方法研究了银原子簇的结构和电子性质。采用TBMD结合遗传算法（GA）对Ag团簇的基态结构进行了优化。通过与小团簇Ag $_n$（n=3-9）的{ \em ab initio}计算结果的比较，证明了紧束缚模型的有效性.发现团簇在n=10时经历了从“电子有序”到“原子有序”的转变。这是由于在这种尺寸下的s-d混合。电子性质，如态密度（DOS），s-d带分离，HOMO-LUMO间隙，和电离势的尺寸依赖性进行了讨论。得到了Ag $_2$，Ag $_8$，Ag $_{14}$，Ag $_{18}$，Ag $_{20}$的幻数行为，与电子椭球壳模型的预测一致.结果表明，钴金属团簇中同时存在电子壳层和几何壳层，它们对团簇的性质起着重要的决定作用。
英文摘要：
Tight-binding molecular dynamics (TBMD) is used to study the structural and electronic properties of silver clusters. The ground state structures of Ag clusters up to 21 atoms are optimized via TBMD combined with genetic algorithm (GA). The detailed comparison with {\em ab initio} results on small Ag$_n$ clusters (n=3-9) proves the validity of the tight-bind model. The clusters are found to undergo a transition from ``electronic order'' to ``atomic order'' at n=10. This is due to s-d mixing at such size. The size dependence of electronic properties such as density of states (DOS), s-d band separation, HOMO-LUMO gap, and ionization potentials are discussed. Magic number behavior at Ag$_2$, Ag$_8$, Ag$_{14}$, Ag$_{18}$, Ag$_{20}$ is obtained, in agreement with the prediction of electronic ellipsoid shell model. It is suggested that both the electronic and geometrical shell exist in the coinage metal clusters and they play a significant role in determining cluster properties.
机构、总结、中文摘要均由AI分析而来，可能存在错误，请以论文正文为准。
