Interstice correlation functions; a new, sensitive characterisation of non-crystalline packed structures
Interstice correlation functions; a new, sensitive characterisation of non-crystalline packed structures
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间隙相关函数；
DOI：
10.1016/0022-3093(81)90116-2
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发表时间：
1981
影响因子：
3.5
通讯作者：
J. Wallace
中科院分区：
文献类型：
--
作者：
J. Finney;J. Wallace
建立了一种致密的软球随机填料作为“理想”单组分金属玻璃的模型。这种结构可以看作是扭曲的八面体和四面体的组合，也可以看作是简单的紧密排列的晶体结构。先前在硬球模型中确定的更复杂的多面体（Bernal孔）在很大程度上被挤出，这是软势所赋予的额外自由体积的结果。讨论了这些基本的四面体和八面体构建块的局部相关性，作为非晶体填充结构的可能特征，以及它们在组成原子周围的组织。这些局部相关性的特征似乎比Voronoi多面体更敏感，更可靠，特别是在检测局部二十面体结构方面。所开发的描述技术的扩展包括加权间隙连通性的检查，使用有关相互连接的大部分三角形“颈”的大小的数据作为加权因子。偏离这种四面体和八面体连接的理想框架可以被认为是缺陷，或者是理想化结构的扭曲，而局部群的相对种群为构型熵计算提供了一种可能的途径。
A dense random packing ofsoftspheres is developed as a model of an “ideal” single component metallic glass. This structure can be considered as an assembly of distorted octahedra and tetrahedra, as can simple close-packed crystal structures. The more complex polyhedra (Bernal holes) previously identified inhardsphere models are largely squeezed out as a result of the additional free volume conferred by the soft potential. Thelocal correlationsof these basic tetrahedral and octahedral building blocks are discussed as possible characterisations of non-crystalline packed structures, together with their organisationaroundthe component atoms. These characterisations of local correlations seem more sensitive and more reliably interpreted than the Voronoi polyhedra, particularly in detecting local icosahedral structures. Extensions of the descriptive techniques developed include examinations of weighted interstice connectivity, using data on the sizes of the interconnecting largely triangular “necks” as weighting factors. Departures from this idealised framework of linked tetrahedra and octahedra can be considered as defects, or distortions from the idealised structure, and the relative populations of local groupings provide a possible route to configurational entropy calculations.