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Title: THE STRUCTURE OF THE FIRST CO-ORDINATION SHELL OF Pb ATOMS IN LEAD-SILICATE GLASSES :A MOLECULAR DYNAMICS STUDY

Creator:

Rybicka Anna

Resource Type:

artykuł

Contributor:

Rybicki Jarosław, Witkowska Agnieszka, Feliziani Sandro, Mancini Giorgio

Abstract:

The structure of lead-silicate glasses, although being investigated for over sixty years, remains still controversial. One of the open questions is the structure of the lead subsystem: what are the basic structural units like, and how are they interconnected. In the literature the appearance of [PbO4]n, or [PbO3]n chains is reported even in the glasses of the same stoichiometry. In order to elucidate the problem of contradicting experimental findings, extensive molecular dynamics (MD) simulations in the isobaric-isoenthalpic (NpH) ensemble of the structure of lead-silicate glasses have been performed in the whole range of glassformation. The atoms were assumed to interact by a two-body Born-Mayer-Huggins interaction potential with full ionic charges. The potential parametrization was taken from Damodaran et al. [Phys. Chem. Glasses, 31, 212 (1990)1. The simulation box contained about 3000 atoms. For each composition an equilibrated ming Pb03 pyramids with the Pb atom in the vertices or in the middle of an al ost flat triangle formed from forapical oxygens of three different SiO4 tetrahedra. Another of all Pb atoms can be qualified as vertices ofrather distorted square pyramids. The remaining of lead atoms have neighbourhoods difficult to classify. For x 0.67 only a few Pb atoms were identified as remaining in the front of a face of a SiO4 tetrahedron. Most of the Pb atoms are placed in the vertices of edge sharing square PbO4 pyramids. Our MD results are compared with available experimental data. 0.1 X 0.33, about of all Pb atoms is either placed in the front of the faces of the SiO4 tetrahedra, forapical oxygens of three different SiO4 tetrahedra. Another of all Pb atoms can be qualified as vertices of rather distorted square pyramids. The remaining of lead atoms have neighbourhoods difficult to classify. For x 0.67 only a few Pb atoms were identified as remaining in the front of a face of a SiO4 tetrahedron.

Place of publishing:

Poznań

Publisher:

OWN

Format:

application/pdf

Resource Identifier:

oai:lib.psnc.pl:501

Language:

eng

Object collections:

Last modified:

Jul 29, 2014

In our library since:

May 22, 2014

Number of object content hits:

293

All available object's versions:

https://lib.psnc.pl/publication/594

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Edition name Date
The Structure of the First Co-Ordination Shell of Pb Atoms in Lead-Silicate Glasses: A Molecular Dynamics Study Jul 29, 2014

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