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MM: Fachverband Metall- und Materialphysik

MM 20: Poster session

MM 20.33: Poster

Dienstag, 27. März 2007, 14:45–18:00, Poster C

Development of an EAM potential for ruthenium — •Frank Römer and Thomas Kraska — Physical Chemistry, University Cologne, Luxemburger Str. 116, D-50939 Köln

The embedded atom method (EAM) is an effective potential model for metals that consists of a functional of the local electron density, being a multibody interaction, and a pairwise additive repulsion potential for the atomic cores. In the context of the development of an EAM potential for the hcp metal ruthenium different concepts are investigated in detail. The ability to reproduce mechanical and caloric properties are analysed for various methods generating the different terms of the potential. Instead of fitting to experimental data, a new analytical expression for the screening function or the effective core charge, based on the electron distribution, is proposed. Because of the lack of knowledge about the effective electron configuration of ruthenium, which is also the case for several other transition metals, the influence of given electron configurations and the resulting electron distribution function on the physical properties is investigated. The properties included here are the stable structure, the lattice constants, and the cohesive energy. In this way the electron configuration can be determined from the associated preferred bulk structure. Vice versa the correlation between the devolution of the electron density and the difference in energetic stability of the two close-packing of spheres, hcp and fcc, are investigated.