Dresden 2014 – wissenschaftliches Programm
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DF: Fachverband Dielektrische Festkörper
DF 4: Glasses (Joint Session with DY and CPP)
DF 4.3: Vortrag
Montag, 31. März 2014, 15:30–15:45, ZEU 146
Simulation of Borate glasses — •Christoph Scherer1,2, Friederike Schmid1, Martin Letz2, and Jürgen Horbach3 — 1Johannes Gutenberg-Universität, Mainz — 2Schott AG, Mainz — 3Heinrich-Heine-Universität, Düsseldorf
The model glass former B2O3 is studied as an example for generating accurate glass structures on the computer. B2O3 is an important component for the simulation of oxide glasses since boron can form triangular planar structures, as well as tetrahedral nearest neighbor structures and also boroxol rings. In one approach, configurations of a few hundred atoms are equilibrated at high temperature, well above the glass transition temperature, with a classical molecular dynamics simulation (MD). After a quench down to 0K, they are structurally relaxed by means of an ab inito (DFT) calculation. The structural and vibrational properties are compared to the results of a full ab inito quench to 0K and to experimental results. The dependence of the glass structure and the liquid properties on the classical force field is examined. Therefore, a set of classical force fields is generated by means of a structural fitting procedure. The parameters are fitted in a way that the structure, namely the radial distribution functions and the angular distributions, of a classical MD run matches as closely as possible the structure of an ab initio (DFT) run at the same temperature. Parameter fits are carried out according to an ab initio trajectory at high temperature, where the system is in the liquid state. This sets the basis for the next steps: The development of a classical force field for sodium-borate glasses by the same methodology.