论文标题
金属簇在石墨上的软着陆：分子动力学研究
Soft landing of metal clusters on graphite: a molecular dynamics study
论文作者
论文摘要
3 nm尺寸Ag $ _ {887} $的结构和稳定性，Au $ _ {887} $和Ti $ _ {787} $簇在软地条件下存放在石墨条件下（$ \ sim 10^{ - 3} -3} -10^{ - 10^0 $ per per per atom perimuntion s Simals of Metheral Dynamerastions。群集表面相互作用的参数来自互补的缩写计算。我们发现表面上的簇的形状受其元素组成的控制，也取决于初始群集结构和着陆条件。在低于0.1 ev/Atom的沉积能量下，Ag $ _ {887} $ cluster获得了椭圆形的形状，而AU $ _ {887} $和Ti $ _ {787} $ clusters分别转变为质量和截断的球形，这是由于强度粘附而构成强度的。簇在表面上扁平，并最终随着沉积能量的增加而瓦解。仿真结果表明，ag $ _ {887} $和au $ _ {887} $片段约为$ 0.75-1.0 $ ev/atom，而较高的能量约为3 ev/atom，对于ti $ _ {787} $的分裂是必需的。接触角，接触半径和簇的高度作为沉积能的功能，是通过将簇表面原子的位置与表面方程式拟合的位置确定的。还分析了这些参数对集群内部能量的依赖性。
Structure and stability of 3 nm size Ag$_{887}$, Au$_{887}$ and Ti$_{787}$ clusters deposited on graphite under soft-landing conditions ($\sim 10^{-3}- 10^0$ eV per atom) are studied by means of molecular dynamics simulations. Parameters for the cluster-surface interaction are derived from complementary ab initio calculations. We found that the shape of clusters on the surface is governed by their elemental composition and depends also on the initial cluster structure and landing conditions. At deposition energies below 0.1 eV/atom, the Ag$_{887}$ cluster acquires an ellipsoidal shape, while Au$_{887}$ and Ti$_{787}$ clusters transform into oblate and prolate truncated spheroids, respectively, due to stronger adhesion to graphite. The clusters flatten over the surface and eventually disintegrate as the deposition energy increases. Simulation results reveal that Ag$_{887}$ and Au$_{887}$ fragment at about $0.75 - 1.0$ eV/atom whereas higher energy of about 3 eV/atom is required for the fragmentation of Ti$_{787}$. The contact angle, contact radius and height of the clusters as functions of deposition energy are determined from fitting the positions of cluster surface atoms with a surface equation. The dependence of these parameters on the internal energy of the clusters is also analyzed.
