Please use this identifier to cite or link to this item: https://apo.ansto.gov.au/dspace/handle/10238/5040
Title: Structure of kaolinite and influence of stacking faults: Reconciling theory and experiment using inelastic neutron scattering analysis
Authors: White, CE
Kearley, GJ
Provis, JL
Riley, DP
Keywords: KAOLINITE
POWDERS
DIFFRACTION
RAMAN SPECTROSCOPY
CRYSTAL STRUCTURE
MINERALS
Issue Date: 21-May-2013
Publisher: American Institute of Physics
Citation: White, C. E., Kearley, G. J., Provis, J. L., & Riley, D. P. (201). Structure of kaolinite and influence of stacking faults: Reconciling theory and experiment using inelastic neutron scattering analysis. Journal of Chemical Physics, 138 (19), 194501.
Abstract: The structure of kaolinite at the atomic level, including the effect of stacking faults, is investigated using inelastic neutron scattering (INS) spectroscopy and density functional theory (DFT) calculations. The vibrational dynamics of the standard crystal structure of kaolinite, calculated using DFT (VASP) with normal mode analysis, gives good agreement with the experimental INS data except for distinct discrepancies, especially for the low frequency modes (200 - 400 cm(-1)). By generating several types of stacking faults (shifts in the a, b plane for one kaolinite layer relative to the adjacent layer), it is seen that these low frequency modes are affected, specifically through the emergence of longer hydrogen bonds (O-H center dot center dot center dot O) in one of the models corresponding to a stacking fault of -0.3151a - 0.3151b. The small residual disagreement between observed and calculated INS is assigned to quantum effects (which are not taken into account in the DFT calculations), in the form of translational tunneling of the proton in the hydrogen bonds, which lead to a softening of the low frequency modes. DFT-based molecular dynamics simulations show that anharmonicity does not play an important role in the structural dynamics of kaolinite. © 2013, American Institute of Physics.
Gov't Doc #: 5081
URI: http://dx.doi.org/10.1063/1.4804306
http://apo.ansto.gov.au/dspace/handle/10238/5040
ISSN: 0021-9606
Appears in Collections:Journal Articles

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