Häkkinen Hannu, Walter Michael, Grönbeck Henrik
Nanoscience Center and Department of Physics, University of Jyväskylä, Finland.
J Phys Chem B. 2006 May 25;110(20):9927-31. doi: 10.1021/jp0619787.
Density functional theory calculations are used to explore phosphine- and thiolate-protected gold nanoclusters, namely, Au(39)(PH(3))(14)Cl(6) and Au(38)(SCH(3))(24). For Au(38)(SCH(3))(24), a novel structural motif is predicted, consisting of ringlike (AuSCH(3))(4) units protecting a central Au(14) core. The calculated optical spectrum of this species features a large optical gap (about 1.5 eV) and a prominently peaked structure, correlating with experimental findings of "molecular-like spectra" of thiolate-protected 1.1 nm gold nanoparticles. Ligand-ligand interactions and steric effects in the ligand shell are suggested as possible driving forces toward an ordered gold core structure. A novel mechanism for ligand-exchange reactions on gold clusters is proposed.
密度泛函理论计算用于探索磷化氢和硫醇盐保护的金纳米团簇，即Au(39)(PH(3))(14)Cl(6)和Au(38)(SCH(3))(24)。对于Au(38)(SCH(3))(24)，预测了一种新颖的结构基序，它由保护中心Au(14)核的环状(AuSCH(3))(4)单元组成。该物种的计算光谱具有较大的光学带隙（约1.5 eV）和明显的峰值结构，这与硫醇盐保护的1.1 nm金纳米颗粒的“分子状光谱”的实验结果相关。配体壳中的配体-配体相互作用和空间效应被认为是形成有序金核结构的可能驱动力。提出了一种金簇上配体交换反应的新机制。
