Examination of Spinel and Nonspinel Structural Models for gamma-Al2O3 by DFT and Rietveld Refinement Simulations
Despite the widespread use of {gamma}-Al{sub 2}O{sub 3}, there is still considerable disagreement over the nature of its structure due to both its poor crystallinity and differing preparation techniques during experimentation. Using density-functional theory (DFT) calculations and Rietveld simulations and refinement, the structure of three spinel-related models and a recently proposed nonspinel model were studied in reference to synchrotron X-ray powder diffraction (SXPD) patterns. The spinel-based structural models represent the structural features of {gamma}-Al{sub 2}O{sub 3} better than the nonspinel model. The major failure of the nonspinel model is that the model cannot reproduce the SXPD reflection originating from tetrahedral aluminum. The Rietveld-refined spinel model can accurately reproduce the lattice parameters and other structural features of {gamma}-Al{sub 2}O{sub 3}, and it can generate a consistent diffraction peak at 2 which lies between the splitting peaks of the experimental pattern that are originated from the disordered tetrahedral aluminum cations.
- Research Organization:
- Brookhaven National Lab. (BNL), Upton, NY (United States). National Synchrotron Light Source
- Sponsoring Organization:
- Doe - Office Of Science
- DOE Contract Number:
- DE-AC02-98CH10886
- OSTI ID:
- 914006
- Report Number(s):
- BNL-78574-2007-JA; JPCBFK; TRN: US0801467
- Journal Information:
- J. Phys. Chem. B, Vol. 110, Issue 5; ISSN 1089-5647
- Country of Publication:
- United States
- Language:
- English
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