^{1}Institute of Metallurgy of Ural Branch of the Russian Academy of Science, Russia

^{2}Stockholm University, Sweden

^{3}Southern Ural State University, Russia

**Keywords:** metal-non-metal transition**property:** diffusion coefficient, atomic structure **material:** cesium, rubidium and mercury

Liquid metals are a convenient object for examinations of the nature and features of density driven metal-dielectric transitions. The cause of this is that the density of metals changes more than 3 times at heating from melting point up to critical point. The data reveals that the precursors of the metal-non-metal transition play an essential role far before critical point. It is possible to assume, that the atomic and electronic structure and dynamics of electrons also essentially change at temperatures far before critical. From the scientific point of view the main interest is to find out how the properties of metals vary with large changes in the density. The first-principles molecular-dynamics methods (FPMD) have become a useful technique to study a wide variety of liquid metal systems. Their basic ingredients are density functional theory, pseudopotential approximation and plane-wave basis set. It is well known that liquid metals show some unusual properties at low densities. The ab initio SIESTA package was used to investigate this phenomenon. In this work the atomic structure and diffusion coefficient of liquid cesium, rubidium and mercury were investigated by means of FPMD for a wide range of temperatures. The calculated structure factors in a good agreement with experimental data. The analysis of atomic configurations is performing by method of Voronoi polyhedron and Delaunay simplexes. The obtained results are compared with those of classical Molecular Dynamics method and experimental data.

Supported by Russian Foundation of the Basic Research - Projects #09-03-00069-а; 11-08-00891-а

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