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Evaluation of domain models for β-cristobalite from the pair distribution function.
Elizabeth R Cope1, Martin T Dove
1Department of Earth Sciences, University of Cambridge, Downing Street, Cambridge CB2 3EQ, UK. ers29@cam.ac.uk
Summary
Domain models fail to explain silica
Area of Science:
- Materials Science
- Solid-State Physics
- Computational Chemistry
Background:
- The high-temperature β-cristobalite phase of silica exhibits significant structural disorder.
- Understanding this disorder is crucial for predicting material properties and behavior.
Purpose of the Study:
- To evaluate the efficacy of domain models in explaining the structural disorder of β-cristobalite silica.
- To compare domain model predictions with experimental data and alternative structural models.
Main Methods:
- Phonon-based computer simulations were employed to calculate the pair distribution function.
- The simulation technique was utilized to generate atomic configurations for comparison with experimental data.
Main Results:
- None of the tested domain models accurately reproduced the experimental pair distribution function of β-cristobalite.
- Previously reported atomic configurations from reverse Monte Carlo (RMC) analysis showed better agreement with experimental data.
- RMC-derived configurations were found to be consistent with the rigid unit mode (RUM) model.
Conclusions:
- Domain models are insufficient to fully explain the structural disorder in β-cristobalite silica.
- The rigid unit mode model provides a more consistent framework for understanding the observed structural disorder.
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