Europhys. Lett., 74 (3), pp. 459-465 (2006)
DOI: 10.1209/epl/i2006-10012-2

Slow dynamics in ion-conducting sodium silicate melts: Simulation and mode-coupling theory

Th. Voigtmann¹ and J. Horbach<sup>2

1</sup>  University of Edinburgh, School of Physics, JCMB The Kings Buildings Mayfield Road, Edinburgh EH9 3JZ, UK
²  Institut für Physik, Johannes-Gutenberg-Universität Mainz Staudinger Weg 7, D-55099 Mainz, Germany

received 1 February 2006; accepted in final form 3 March 2006
published online 29 March 2006

Abstract
Calculations within the mode-coupling theory of the glass transition (MCT) are used to elucidate the structure-dynamics relation in sodium-silicate melts (NSx) of varying sodium concentration. Using only the partial static structure factors from molecular-dynamics (MD) computer simulation as input, MCT qualitatively reproduces the large separation in relaxation time scales between the sodium and the silicon/oxygen components peculiar to such mixtures. This shows that it is possible to explain the fast sodium-ion dynamics observed in sodium-silicate melts using MCT as a microscopic theory, and from the averaged equilibrium structure alone.

PACS
64.70.Pf - Glass transitions.
61.20.Ja - Computer simulation of liquid structure.
66.30.Hs - Self-diffusion and ionic conduction in nonmetals.

© EDP Sciences 2006