Department of Physical Chemistry, Institute of Chemical Technology Prague, Technická 6, 166 28 Prague 6, Czech Republic.
Phys Chem Chem Phys. 2010 Feb 7;12(5):1152-61. doi: 10.1039/b918186e. Epub 2009 Dec 10.
Ab initio calculations are used to construct an analytical many-body potential for Pb(2+)He(n) and Pb(+)He(n) clusters which accounts for non pairwise additive interactions. The potential surface reproduces the global minima for cluster sizes ranging from n = 1 to n = 16 obtained from explicit ab initio calculations and found in a previous search for ultrahigh coordination numbers. Ground state energies and structures obtained by accurate diffusion quantum Monte Carlo calculations are used to investigate if quantum effects qualitatively affect the formation of coordination shells. For Pb(2+) doped clusters a first solvation shell is closed at n = 12 and gradually softened by additional helium atoms which start to form a distinct second shell only at n = 16. Spin-orbit coupling profoundly influences the structure of Pb(+)He(n) clusters and causes a gradual structural evolution without pronounced solvation shells.
从头算方法被用于构建一个能够描述 Pb(2+)He(n) 和 Pb(+)He(n) 团簇中非成对附加相互作用的分析多体势。该势能表面再现了从 n = 1 到 n = 16 的团簇大小的全局最小值，这些最小值是通过明确的从头算计算得到的，并在前一次对超高配位数的搜索中被发现。通过精确的扩散量子蒙特卡罗计算得到的基态能量和结构被用来研究量子效应对配位壳形成的定性影响。对于 Pb(2+)掺杂的团簇，在 n = 12 时形成了第一个溶剂化壳，并且随着氦原子的增加逐渐变软，只有在 n = 16 时才开始形成明显的第二个壳。自旋轨道耦合深刻地影响了 Pb(+)He(n)团簇的结构，并导致了没有明显溶剂化壳的逐渐结构演化。
