Interatomic voids in analysis of computer model structures of liquids and glasses

To analyze the structure of noncrystalline systems (liquids, glasses), it is suggested that the functions to be calculated should include not only the conventional atom-atom radial distribution function and structural factor, but also the same functions for a system of points representing the centers of interatomic voids. The points are located at the nodes of Voronoi polyhedra or, which is equivalent, at the centers of the spheres circumscribed around the Delaunay simplices. The system of points (system {D}) is unambiguously defined by the atomic coordinates and conveys additional information on the structure of the system because each interatomic void is determined by the relative positions of several atoms. Using a homogeneous noncrystalline packing model of atoms and inhomogeneous models derived from it as an example, we demonstrate that system {D} is sensitive to the structural features on medium scales and may be used along with the conventional atom-atom functions to study structural correlations other than short-range order correlations.