Multicomposition EPSR: toward transferable potentials to model chalcogenide glass structures

Towey, James J. and Barney, Emma R. (2016) Multicomposition EPSR: toward transferable potentials to model chalcogenide glass structures. Journal of Physical Chemistry B . ISSN 1520-5207

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Abstract

The structure of xAs40Se60–(1 – x)As40S60 glasses, where x = 1.000, 0.667, 0.500, 0.333, 0.250, and 0.000, is investigated using a combination of neutron and X-ray diffraction coupled with computational modeling using multicomposition empirical potential structure refinement (MC-EPSR). Traditional EPSR (T-EPSR) produces a set of empirical potentials that drive a structural model of a particular composition to agreement with diffraction experiments. The work presented here establishes the shortcomings in generating such a model for a ternary chalcogenide glass composition. In an enhancement to T-EPSR, MC-EPSR produces a set of pair potentials that generate robust structural models across a range of glass compositions. The structures obtained vary with composition in a much more systematic way than those taken from T-EPSR. For example, the average arsenic–sulfur bonding distances vary between 2.28 and 2.46 Å in T-EPSR but are 2.29 ± 0.02 Å in MC-EPSR. Similarly, the arsenic–selenium bond lengths from T-EPSR vary between 2.28 and 2.43 Å but are consistently 2.40 ± 0.02 Å in the MC-EPSR results. Analysis of these models suggests that the average separation of the chalcogen (S or Se) atoms is the structural origin of the changes in nonlinear refractive index with glass composition.

Item Type: Article
Additional Information: This document is the unedited Author’s version of a Submitted Work that was subsequently accepted for publication in Journal of Physical Chemistry B, copyright © American Chemical Society after peer review. To access the final edited and published work see http://pubs.acs.org/doi/abs/10.1021/acs.jpcb.6b08793
Schools/Departments: University of Nottingham, UK > Faculty of Engineering
Identification Number: 10.1021/acs.jpcb.6b08793
Depositing User: Eprints, Support
Date Deposited: 20 Dec 2016 11:11
Last Modified: 16 Sep 2017 06:02
URI: http://eprints.nottingham.ac.uk/id/eprint/39455

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