Regensburg 2013 – wissenschaftliches Programm
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DY: Fachverband Dynamik und Statistische Physik
DY 10: Glasses (joint session DY/DF/CPP)
DY 10.1: Vortrag
Dienstag, 12. März 2013, 09:30–09:45, H46
Towards reliable structural information of multicomponent glass systems — •Christoph Scherer1,2, Friederike Schmid1, and Martin Letz2 — 1Johannes Gutenberg-Universität, Mainz, Deutschland — 2Schott AG, Mainz, Deutschland
Glasses have a huge range of applications, however, they are still theoretically not well understood. Also experimental access to the structure of glasses is limited. This motivates the study of glass systems by means of computer simulations.
In this work, a set of glass structures is generated on the computer by equilibrating a system of a few hundred atoms at high temperature, well above the glass transition temperature, with a classical molecular dynamics simulation (MD). Afterwards the system is cooled down to 0 K and structurally relaxed to the next (local) minimum by means of a quantum mechanical density functional (DFT) calculation. The glass properties before and after the structural relaxation are compared to experimental results. Especially, the phonon density of states is of interest, as it provides access to thermodynamical quantities.
This sets the basis for the next steps: The force fields for the MD simulation are generated by means of a structural fitting procedure. Here, the force field parameters are fitted in a way that the structure, namely the radial distribution function, of a short MD run at high temperature matches as closely as possible that one of a short DFT run at the same temperature. The dependence of the fitting accuracy of the classical force field on the final glass structure and glass properties is examined.