STATISTICS OF VORONOI CELLS OF SLIGHTLY PERTURBED FACE-CENTERED-CUBICAND HEXAGONAL CLOSE-PACKED LATTICES

We have studied theoretically and by numerical simulations the topolog ical properties of Voronoi tessellations of slightly perturbed fee and hcp lattices. The number f of faces of a cell can go from 12 to 18 wi th a mean value [f] = 14 very different from the value 12 in the non-p erturbed lattices. A face can have 4, 5 or 6 sides; we give the percen tages of each type of face both in the cells with given values of f an d in the whole tessellation. The study of the topological correlations between neighbouring cells shows that Aboav-Weaire's law is valid.