Ceramics-Silikáty 53, (2) 137 - 140 (2009) |
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ELASTIC PROPERTIES OF SODA-LIME SILICA GLASS FROM FIRST PRINCIPLES
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Macháček Jan 1, Gedeon Ondřej 1, Liška Marek 2
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1 Department of Glass and Ceramics, Institute of Chemical Technology, Technicka 5, Prague 166 28, Czech Republic
2 Vitrum Laugaricio – Joint Glass Center of Institute of Inorganic Chemistry SAS, Alexander Dubcek University of Trencin and
RONA Lednicke Rovne, Studentska 2, Trencin 911 50, Slovak Republic
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Keywords: Ab initio molecular dynamics, Soda-lime-silica glass, Structure, Elastic constants, Size effects, Silicate rings
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This work describes preparation of soda-lime-silica (NCS) window glass by the first principles molecular dynamics and
calculation of elastic properties from the Hellman-Feynman stresses. Small atomic glassy systems reveal deviations from
isotropic solid. Such deviations can be quantified using differences among some stress tensor components. The first principles
model applied in this work (DFT: PBE/PAW) underestimates elastic constants by 10-20 %. Size effects were studied with
help of the classical molecular dynamics of binary glass Na₂O·3SiO₂ which is close to NCS glass stoichiometry. It was found
that elastic properties of small atomic systems are essentially size-independent even if silicate ring statistics reveals strong
dependence on the number of atoms. |
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