Reverse Monte Carlo modelling of Eu and Tb metaphosphate glasses

Mountjoy, Gavin and Anderson, Ruth and Bowron, Daniel Timothy and Newport, Robert J. (1997) Reverse Monte Carlo modelling of Eu and Tb metaphosphate glasses. In: 7th International Conference on the Structure of Non-Crystalline Materials (NCM7), Sep 15-19, 1997, Cagliari, Italy. (Access to this publication is restricted)

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http://dx.doi.org/10.1016/S0022-3093(98)00384-6

Abstract

It is possible to make phosphate glasses (R2O3)(x)(P2O5)(1-x) With contents of rare-earth elements, R, close to the metaphosphate composition, R(PO3)(3). These glasses are particularly stable to water, and have interesting optical, acoustic and magnetic properties. We have modelled Eu and Tt, metaphosphate glasses using the reverse Monte Carlo (RMC) technique with X-ray diffraction data. The model building process must include additional constraints, and we have derived these from knowledge of metaphosphate structures, including metaphosphate crystals. The model building procedure was first to fit structural constraints alone, and then to fit the diffraction data while maintaining the structural constraints. The models constructed consist of chains of phosphate tetrahedra with Eu (or Tb) 6-fold coordinated to non-bridging oxygens (NBOs), and are in good agreement with the diffraction data. Thus the models provide a demonstration of validity of this structural description of rare-earth metaphosphate glasses. In addition, two different values were used for minimum rare-earth separation, 3.9 and 5.4 Angstrom, based on two different metaphosphate crystals, and more satisfactory models were obtained when using the shorter distance.

Item Type: Conference or workshop item (Paper)
Additional information: Presidenza Giunta Reg; Reg Autonoma Sardegna, Assessorato Affari Gen; Camera Commercio Ind Artigianato & Agr; EMSA, Ente Minerario Sardo; Fdn Banco Sardegna; Univ Cagliari; CNR, Com Chim; INCM, Consorzio Interuniv Nazl Chim Mat; SARAS Raffinerie Sarde; Comune Iglisias; Assoc Univ Sulcis Iglesiente; Ente Sardo Ind Turistiche
Subjects: Q Science
Divisions: Faculties > Science Technology and Medical Studies > School of Physical Sciences > Functional Materials Group
Depositing User: M.A. Ziai
Date Deposited: 29 Mar 2009 20:03
Last Modified: 11 Apr 2014 13:09
Resource URI: http://kar.kent.ac.uk/id/eprint/17461 (The current URI for this page, for reference purposes)
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