The Voronoi Polyhedra as tools for structure determination in simple disordered systems

J.C. Gil Montoro and J.L.F. Abascal

ABSTRACT

The structure of some simple fluids is analyzed through the Voronoi tessellation of the configurations generated by computer simulation. Special emphasis is put on the investigation of disordering, i.e., the deviation from solid state properties. The models studied include a simple Lennard-Jones (LJ) liquid, two quenched states obtained from the liquid, and a system made of non-interacting particles (the ideal gas) while a state point corresponding to the LJ solid phase is used as reference. To perform the Voronoi construction, an algorithm specially suited for disordered systems is presented. The arrangement of particles has been studied through the geometrical features of their Voronoi Polyhedra (VP). It is shown that two parameters can give a description of the VP in such a way that the disordering of the system is clearly manifested. One is the volume distribution coefficient of skewness and the other is the shape of the VP as described by the convex bodies non-sphericity factor. In particular, the clusters present in a rapidly quenched liquid are easily revealed in this way.

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