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Iron phosphate glasses: structure determination and displacement energy thresholds, using a fixed charge potential model

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journal contribution
posted on 2015-03-04, 12:43 authored by Kitheri Joseph, Kenny JolleyKenny Jolley, Roger Smith
Iron phosphate glass is a versatile matrix for the immobilisation of various radioactive elements found in high-level nuclear waste (HLW). Quenched glass structures of iron phosphate glasses with Fe/P ratios of 0.33, 0.67 and 0.75 and with a composition of 40 mol% Fe2O3 and 60 mol% P2O5, with 4% and 17% Fe2 + ion concentrations were generated using molecular dynamics and the threshold displacement energies calculated. In the minimum energy structures, we found that in nearly all cases the P atoms were 4-fold coordinated. The potential energy per atom increased with increasing concentration of Fe2 + ions with similar Fe/P ratio, suggesting that decreasing the Fe2 + content is a stabilising factor. The average bond distances between Fe2 +-O, Fe3 +-O, P-O and O-O were calculated as 2.12, 1.88, 1.5 and 2.5 Å respectively. The threshold displacement energy (Ed) was found to be dependent upon the ion specie, less for Fe2 + ions compared to Fe3 + ions, and was overall slightly lower than that determined for borosilicate glass.

Funding

This work was supported by the Engineering and Physical Sciences Research Council [grant number EP/K007882/1].

History

School

  • Science

Department

  • Mathematical Sciences

Published in

Journal of Non-Crystalline Solids

Volume

411

Pages

137 - 144

Citation

JOSEPH, K., JOLLEY, K. and SMITH, R., 2015. Iron phosphate glasses: Structure determination and displacement energy thresholds, using a fixed charge potential model. Journal of Non-Crystalline Solids, 411 pp.137-144.

Publisher

Elsevier (© the authors)

Version

  • VoR (Version of Record)

Publisher statement

This work is made available according to the conditions of the Creative Commons Attribution 4.0 International (CC BY 4.0) licence. Full details of this licence are available at: http://creativecommons.org/licenses/ by/4.0/

Publication date

2015

Notes

This work is made available according to the conditions of the Creative Commons Attribution 4.0 Unported (CC BY 4.0) licence. Full details of this licence are available at: http://creativecommons.org/licenses/by/4.0/

ISSN

0022-3093

Language

  • en