Cu87团簇在升温与急冷过程中结构变化的原子尺度模拟

本文采用基于嵌入原子法的正则系综分子动力学方法在原子尺度上计算了包含87个原子的Cu87金属团簇在连续升温和急冷降温时的结构演化过程。根据原子平均势能、对分布函数、原子堆积结构和主要原子键对数目随温度的变化表明，温度的不同极大地影响团簇内的原子堆积结构。在升温过程中，随着温度的升高，团簇内原子堆积结构出现由密排六方、二十面体直到无序堆积的变化。在急冷降温过程中，随着急冷温度的降低，团簇内由出现的一定数量的二十面体和面心立方的局域结构、数量不一的HCP，FCC和二十面体局域结构，直到急冷温度较低时的一定数量的二十面体局域结构。

Modelling structural changes of a Cu87 cluster on heating and quenching by molecular dynamics

The structural change of a Cu87 cluster on heating and quenching is investigated by NVT molecular dynamics simulations within the framework of embedded atom method. On the basis of analyses of average energy per atom, pair distribution functions, atom packing, and pair numbers varying with the temperature, it is shown that the temperature greatly affect the atom packing in this cluster. On heating, the atom packing of this cluster presents the changes from HCP, icosahedron, to the disordered packing with increasing the temperature. On quenching,there are some icosahedral and FCC local structures, and a certain numbers of HCP, FCC, and icosahedral structures with decreasing the quenching temperature. At a low quenching temperature, amount of the locally icosahedral structures are observed.