Local structures in medium-sized Lennard-Jones clusters: Monte Carlo simulations
Local structures in medium-sized Lennard-Jones clusters: Monte Carlo simulations
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中型 Lennard-Jones 星团中的局部结构：蒙特卡罗模拟
DOI：
10.1103/physrevb.67.115402
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发表时间：
2003
影响因子：
3.7
通讯作者：
A. Patrykiejew
中科院分区：
文献类型：
--
作者：
W. Polak;A. Patrykiejew
在${T}^{*}=0.05$和${T}^{*}=0.49的还原温度范围内，用正则蒙特卡罗方法模拟了由大约200个原子组成的Lennard-Jones团簇。基于面心立方（fcc）、六边形密排（hcp）、二十面体（ic）、五边形直排（pdp）和体心立方（bcc）五种正配多面体的局部结构分类，采用一种特别发明的算法对簇内原子的局部排列进行了识别。三种完美晶体（fcc、hcp和bcc）的团簇在固体团簇对应的温度范围内，随着温度的逐渐升高，团簇呈现出结构转变。201个原子簇在温度${T}^{*}=0.25$时形成，原子位置随机，具有多种局部结构，hcp和pdp结构单元数量优势，bcc结构单元缺失。这些团簇大多是多面体，通常表现为ic单元的三角形或四面体排列。在一些团簇中，不存在非晶化和pdp原子排列。在这种情况下，两个晶体相的空间分离可以以fcc和hcp畴的形式或夹心平行fcc和hcp平面的形式观察到。
The Lennard-Jones clusters composed of approximately 200 atoms were simulated using canonical Monte Carlo method at the reduced temperatures between ${T}^{*}=0.05$ and ${T}^{*}=0.49.$ Local arrangements of atoms within the clusters were identified by means of a specially invented algorithm based on the classification of five types of regular coordination polyhedra corresponding to face-centered cubic (fcc), hexagonal close-packed (hcp), icosahedral (ic), pentagonal direct-packed (pdp), and body-centered cubic (bcc) local structures. Clusters cut off from three types (fcc, hcp, and bcc) of perfect crystals show a structural transition with gradually increasing temperature in the temperature range corresponding to solid clusters. The spectrum of 201 atomic clusters formed at the temperature ${T}^{*}=0.25$ from a starting configuration with random atom positions is characterized by a variety of local structures, with quantitative dominance of hcp and pdp structural units and absence of bcc units. Most of these clusters are polyicosahedral, very often showing a triangular or tetrahedral arrangement of ic units. In some clusters noncrystallographic ic and pdp atom arrangement is absent. In such cases spatial separation of two crystallographic phases can be observed in the form of fcc and hcp domains or as sandwiched parallel fcc and hcp planes.