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

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.