The lattice dynamics of 19 compounds with the sodium chloride structure have been investigated using shell models. The models are compared with existing experimentally measured phonon-dispersion curves and refined using a multidimensional downhill simplex method. Debye-Waller factors for these compounds are calculated over the temperature range from 1 to 1000 K where appropriate and the results are fitted analytically using polynomial regression. The results are compared with experimentally measured room-temperature Debye-Waller factors and for most of the compounds the agreement is found to be better than 10%. At lower temperatures, it is expected that these results would be more accurate, since the harmonic approximation, which is crucial to the calculation of the Debye-Waller factors, works better. In choosing the models for particular applications, it is recommended that the model with the smallest standard error σ is used for fitting the experimentally measured phonon-dispersion curves, or the model that shows best agreement with reliable experimental measurements of more relevant physical quantities, such as Debye-Waller factors in crystallography.
|Original language||English (US)|
|Number of pages||12|
|Journal||Acta Crystallographica Section A: Foundations of Crystallography|
|State||Published - Jan 1 1999|
ASJC Scopus subject areas
- Structural Biology