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Journal ArticleDOI

Aggregation of tetrahedral and quartoctahedral Delaunay simplices in liquid and amorphous rubidium

N N Medvedev
- 19 Nov 1990 - 
- Vol. 2, Iss: 46, pp 9145-9154
TLDR
In this article, simplicial configurations of a tetrahedral and quartoctahedral form are considered for molecular-dynamic models of liquid and quenched rubidium and the results of a detailed analysis of finite clusters, depending on the fraction of coloured sites for different colours, are proposed.
Abstract
Simplicial atomic configurations (four nearest atoms, defining the Delaunay simplices) are considered for molecular-dynamic models of liquid and quenched rubidium. The aggregates, involving simplicial configurations of a tetrahedral and quartoctahedral form are studied. The problem is reduced by the general Voronoi-Delaunay approach to the study of clusters of the coloured sites on the Voronoi network in terms of percolation theory. The results of a detailed analysis of finite clusters, depending on the fraction of coloured sites for different colours, are proposed. The simplicial atomic configurations, close in shape to regular tetrahedra, determine the T-coloured sites on the Voronoi network and those close in shape to regular quartoctahedra determine the O-coloured ones. Small, medium and large clusters and the backbones of finite ones are studied for this model. The percolation thresholds are determined for the T and O colouring. A topological similarity between the aggregates of tetrahedral simplices in liquid and quenched states is revealed. The significant role of the quartoctahedral simplicial configurations in the quenched state structure is emphasized.

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Citations
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Journal ArticleDOI

Ultrastable glasses from in silico vapour deposition

TL;DR: This work creates ultrastable glasses by means of a computer-simulation process that mimics physical vapour deposition, and shows that the glasses' extraordinary stability is associated with distinct structural motifs, in particular the abundance of regular Voronoi polyhedra and the relative lack of irregularpolyhedra.
Journal ArticleDOI

Polytetrahedral Nature of the Dense Disordered Packings of Hard Spheres

TL;DR: The structure of numerically simulated hard sphere packings at different densities is studied by investigating local tetrahedral configurations of the spheres, finding that at the Bernal's limiting density the polytetrahedral packing cannot provide further increase in the density, and alternative structural change begins henceforth.
Journal ArticleDOI

A statistical analysis of void size distribution in a simulated narrowly graded packing of spheres

TL;DR: In this article, the void microstructure of a simulated packing of polydisperse spheres has been investigated by means of a radical Delaunay tessellation, and the void structure is quantified in terms of probability density functions of pore and constriction sizes, cumulative distributions and connectivity functions.
Journal ArticleDOI

The structural origin of the hard-sphere glass transition in granular packing

TL;DR: This study essentially identifies a long-sought-after structural glass order in hard-sphere glasses that is spatially correlated with the slow dynamics and follows an entropy-driven nucleation process, similar to that of the random first-order transition theory.
Journal ArticleDOI

Theory of structural transformation in lithiated amorphous silicon.

TL;DR: First-principles calculations of the structure of a-Si at different lithiation levels using Voronoi-Delaunay methods and ring statistics show that a-LixSi has a fundamentally different structure below and above a lithiation level corresponding to x ∼ 2.
References
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Journal ArticleDOI

Interstice correlation functions; a new, sensitive characterisation of non-crystalline packed structures

TL;DR: In this paper, a dense random packing of soft spheres is developed as a model of an idealized single component metallic glass, and local correlations of these basic tetrahedral and octahedral building blocks are discussed as possible characterisations of non-crystalline packed structures, together with their organisation around the component atoms.
Journal ArticleDOI

Shape of the Delaunay simplices in dense random packings of hard and soft spheres

TL;DR: In this paper, two shape parameters for Delaunay simplices are proposed which allow one to recognize slightly distorted tetrahedral and octahedral simplices, and these simplex types are found to be the basic building units in dense packings of hard and soft spheres.
Journal ArticleDOI

Statistics of Voronoi Polyhedra in Rapidly Quenched Monatomic Liquids. I. Changes during Rapid-Quenching Process

TL;DR: In this article, the Voronoi polyhedron was analyzed for the computer simulated states of liquid rubidium in the rapid quenching process from the melting point down to near the liquid helium temperature.
Journal ArticleDOI

Structure of simple liquids as a percolation problem on the Voronoi network

TL;DR: In this paper, the mutual arrangement of Delaunay simplices is formulated as a site-correlated percolation problem on the Voronoi network and typical cluster configurations of simplices of tetrahedral and octahedral form (the main structural elements of simple liquids) are found.
Journal ArticleDOI

Molecular Dynamics Study of the Structure of a Rapidly Quenched Metal

TL;DR: In this paper, the molecular dynamics method is used to simulate the rapid quenching process of a simple liquid metal, and the model consists of 864 particles with the density-dependent effective pair potential, which can describe the structure of liquid rubidium above the melting point.
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