A novel Delaunay simplex technique for detection of crystalline nuclei in dense packings of spheres

Abstract

The paper presents a new approach for revealing regions (nuclei) of crystalline structures in computer models of dense packings of spherical atoms using the Voronoi-Delaunay method. A simplex Delaunay, comprised of four atoms, is a simplest element of the structure. All atomic aggregates in an atomic structure consist of them. A shape of the simplex and the shape of its neighbors are used to determine whether the Delaunay simplex belongs to a given crystalline structure. Characteristics of simplexes defining their belonging to FCC and HCP structures are studied. Possibility to use this approach for investigation of other structures is demonstrated. In particular, polytetrahedral aggregates of atoms untypical for crystals are discussed. Occurrence and growth of regions in FCC and HCP structures is studied on an example of homogeneous nucleation of the Lennard-Jones liquid. Volume fraction of these structures in the model during the process of crystallization is calculated. © Springer-Verlag Berlin Heidelberg 2005.