Ref Arxiv: 0804.2654
Ref. & Cit.: NASA ADS
Résumé:

A Molecular Dynamics (MD) study of static and dynamic properties of moltenand glassy germanium dioxide is presented. The interactions between the atomsare modelled by the classical pair potential proposed by Oeffner and Elliott(OE) [Oeffner R D and Elliott S R 1998, Phys. Rev. B, 58, 14791]. We compareour results to experiments and previous simulations. In addition, an ab initiomethod, the so-called Car-Parrinello Molecular Dynamics (CPMD), is applied tocheck the accuracy of the structural properties, as obtained by the classicalMD simulations with the OE potential. As in a similar study for SiO2, thestructure predicted by CPMD is only slightly softer than that resulting fromthe classical MD. In contrast to earlier simulations, both the static structureand dynamic properties are in very good agreement with pertinent experimentaldata. MD simulations with the OE potential are also used to study therelaxation dynamics. As previously found for SiO2, for high temperatures thedynamics of molten GeO2 is compatible with a description in terms of modecoupling theory.

Commentaires: 27 pages, 16 figures