Götz D A, Shayeghi A, Johnston R L, Schwerdtfeger P, Schäfer R
Eduard-Zintl-Institut für Anorganische und Physikalische Chemie, Technische Universität Darmstadt, 64287 Darmstadt, Germany.
School of Chemistry, University of Birmingham, Edgbaston, Birmingham B15 2TT, United Kingdom.
J Chem Phys. 2014 Apr 28;140(16):164313. doi: 10.1063/1.4872369.
Combining molecular beam electric deflection experiments and global optimization techniques has proven to be a powerful tool for resolving equilibrium structures of neutral metal and semiconductor clusters. Herein, we present electric molecular beam deflection experiments on PbN (N = 7-18) clusters. Promising structures are generated using the unbiased Birmingham Cluster Genetic Algorithm approach based on density functional theory. The structures are further relaxed within the framework of two-component density functional theory taking scalar relativistic and spin orbit effects into account. Quantum chemical results are used to model electric molecular beam deflection profiles based on molecular dynamics calculations. Comparison of measured and simulated beam profiles allows the assignment of equilibrium structures for the most cluster sizes in the examined range for the first time. Neutral lead clusters adopt mainly spherical geometries and resemble the structures of lead cluster cations apart from Pb10. Their growth pattern deviates strongly from the one observed for tin and germanium clusters.
事实证明，将分子束电偏转实验与全局优化技术相结合是解析中性金属和半导体团簇平衡结构的有力工具。在此，我们展示了对PbN（N = 7 - 18）团簇进行的电分子束偏转实验。基于密度泛函理论，使用无偏伯明翰团簇遗传算法生成有前景的结构。在考虑标量相对论和自旋轨道效应的双组分密度泛函理论框架内，对这些结构进一步进行弛豫处理。基于分子动力学计算，利用量子化学结果对电分子束偏转轮廓进行建模。测量和模拟束轮廓的比较首次使得能够为所研究范围内的大多数团簇尺寸确定平衡结构。中性铅团簇主要采用球形几何结构，除了Pb10之外，与铅团簇阳离子的结构相似。它们的生长模式与锡和锗团簇所观察到的模式有很大偏差。
