Dresden 2003 – wissenschaftliches Programm

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DY: Dynamik und Statistische Physik

DY 31: Glasses Ib (joined session FV DF/DY)

DY 31.5: Vortrag

Dienstag, 25. März 2003, 11:15–11:30, HSZ/403

The Mixed Alkali Effect in Sodium Silicates: Computer Simulation Studies — •Hans Knoth, Jürgen Horbach und Kurt Binder — Institut für Physik, Johannes Gutenberg–Universität, Staudinger Weg 7, D-55099 Mainz

Molecular dynamics computer simulations are used to investigate the Mixed Alkali Effect (MAE) in systems of the form (1−x)Li₂O· xK₂O·2SiO₂ (0≤ x ≤ 1). In order to model the interactions between the atoms we use the potential proposed by Habasaki and Okada (Mol. Simul. 9, 319 (1992)). The simulations are done at constant pressure (p_ext=0) for systems of 8064 particles. The structure and dynamics is studied for molten systems, i.e. at temperatures where the systems can be fully equilibrated (on a time scale of about 20 ns), as well as at lower temperatures at which only the alkali ions show a diffusive motion. We discuss the origin of the MAE by means of time–dependent density–density correlation functions.