The Ag-rich clusters Ag(Ag2S)n and Ag2(Ag2S)n (n = 1-6) are studied by the genetic algorithm combined with the density functional theory method. The PBE0/Lanl2tz(Ag)/6-311G(d,p)(S) method is used to optimize the structures. The global minimum structures, HOMO and LUMO frontier orbitals, and increment mechanisms of the clusters are investigated. The S–Ag–S unit is present in the structure when n > 1 for Ag(Ag2S)n and Ag2(Ag2S)n (n = 1-6) clusters. The triangular Ag3S3 unit is found to be an elemental building block to construct Ag(Ag2S)n and Ag2(Ag2S)n (n = 3-6) clusters. The S–Ag–Ag–S unit is present in the structures of Ag(Ag2S)5 and Ag(Ag2S)6 clusters. Beginning from Ag(Ag2S), the increment progress is exothermic when one Ag2S molecule or Ag atom is added to the molecule. The structural evolution of the studied clusters follows an edge-to-face growth mechanism. As the clusters increase, the structures evolve from open to cage ones.

中文翻译：

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富银团簇结构和生长机制的理论研究：Ag(Ag2S)n 和 Ag2(Ag2S)n (n = 1–6)

利用遗传算法结合密度泛函理论方法研究了富银团簇Ag(Ag2S)n和Ag2(Ag2S)n(n=1-6)。PBE0/Lanl2tz(Ag)/6-311G(d,p)(S) 方法用于优化结构。研究了团簇的全局最小结构、HOMO和LUMO前沿轨道以及增量机制。当 Ag(Ag2S)n 和 Ag2(Ag2S)n (n = 1-6) 簇的 n > 1 时，结构中存在 S–Ag–S 单元。发现三角形 Ag3S3 单元是构建 Ag(Ag2S)n 和 Ag2(Ag2S)n (n = 3-6) 簇的基本构件。S-Ag-Ag-S 单元存在于 Ag(Ag2S)5 和 Ag(Ag2S)6 簇的结构中。从 Ag(Ag2S) 开始，当一个 Ag2S 分子或 Ag 原子添加到分子中时，增量过程是放热的。所研究的簇的结构演化遵循边对面的生长机制。随着簇的增加，结构从开放式演变为笼式结构。