Time-Disordered Crystal Structure of AlPO4-5
| Autor: | Garry J. McIntyre, Dehong Yu, N. R. de Souza, Narendirakumar Narayanan, Bethany R. McBride, David L Cortie, Richard A. Mole, Yun Liu, Maxim Avdeev, Gordon J. Kearley, Raymond Withers |
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| Rok vydání: | 2017 |
| Předmět: |
Diffraction
Work (thermodynamics) Chemistry 02 engineering and technology Crystal structure 010402 general chemistry 021001 nanoscience & nanotechnology 01 natural sciences Symmetry (physics) Inelastic neutron scattering 0104 chemical sciences Surfaces Coatings and Films Electronic Optical and Magnetic Materials Crystallography General Energy Chemical physics Ab initio quantum chemistry methods Tetrahedron Plastic crystal Physical and Theoretical Chemistry 0210 nano-technology |
| Zdroj: | The Journal of Physical Chemistry C. 121:18762-18770 |
| ISSN: | 1932-7455 1932-7447 |
| Popis: | Modern ab initio calculations have become increasingly accurate for predicting the symmetry of crystal structures; however, the standard methods usually only determine the 0 K static configuration and therefore misrepresent structures where dynamics play a key role. In this work, we demonstrate a clear experimental example of this phenomenon in the AlPO4-5 molecular sieve where the average high-symmetry P6cc structure emerges from local dynamics involving corner-sharing tetrahedra. Quasielastic and inelastic neutron scattering experiments were conducted to clarify the thermally activated motions between 1.5 and 300 K. Through comparison with ab initio molecular dynamics, we explain why the theoretically predicted structure is not observed in diffraction experiments. Instead, the results indicate this material is an inorganic analogue of a plastic crystal where thermal dynamics dictate the average symmetry. |
| Databáze: | OpenAIRE |
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