An analysis of voids and necks in supercritical water

Abstract

The characterization of voids in liquids is important in understanding the behavior of many physical properties. In this work, we have used the Voronoi polyhedra method, coupled with its complementary analysis of Delaunay tessellation, to investigate the changes in the local structure of supercritical water of varying densities. Calculations are done at three different supercritical densities of 1.0, 0.7 and 0.35 g cm− 3 at 673 K and also of normal water at 298 K. In addition, a further lower density of 0.15 g cm− 3 is also considered at the same supercritical temperature. It is found that the volume available to the particles and the void radius increase with the decrease in density at a given temperature. The distributions of radii of necks connecting two neighboring voids are also calculated and their changes with variation of density and temperature are discussed.