Void space analysis of the structure of liquids

Abstract

Different types of the intermediate range order are modelled with help of extra voids added in the dense non-crystalline packing of 27000 Lennard-Jones atoms. The voids are created by removing 15% of the atoms from the original packing according to a stencil with a given structural motif: crystalline, random and non-crystalline (like to dense non-crystalline packing). Radial distribution function and the structure factor are calculated both for the atomic centres and for the centres of the interstitial spheres — Delaunay simplex circumcentres. These centres lie “in the depth” in empty space between atoms and therefore reflect a spatial distribution of voids. It is shown that the system of Delaunay simplex circumcentres is sensitive to the structure peculiarities of the models, while the atom-atom correlations are not very indicative in this case. A length scale contained in the distribution of voids causes a peak in the void-void structure factor and also a sharp prepeak (FSDP) in the atom-atom structure factor at the same position. The features of the structure factor governed by the intermediate range order can be recognised by the analysis of voids at the computer simulation of liquids and glasses.