Theoretical study of kaolinite

Castro, Elton Anderson Santos de; Martins, João B. L.

doi:10.1002/qua.20547

Cited by 27 publications

(25 citation statements)

References 51 publications

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“…[51][52][53][54][55][56][57][58][59][60][61][62][63][64][65][66][67] However, dispersioncorrected DFT approach was used only in two works: DFT-D2 15 and vdW-TS 22 methods were applied in the calculations of structural parameters of pyrophyllite 46 while the B3LYP-D2 method was used in the study of kaolinite. 64 In both studies a significant improvement of the structural parameters, especially in a direction of layer stacking, was observed.…”

Section: Introductionmentioning

confidence: 99%

Assessment of ten DFT methods in predicting structures of sheet silicates: Importance of dispersion corrections

Tunega

Bučko

Zaoui

2012

The Journal of Chemical Physics

122

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The performance of ten density functional theory (DFT) methods in a prediction of the structure of four clay minerals, in which non-bonding interactions dominate in the layer stacking (dispersive forces in talc and pyrophyllite, and hydrogen bonds in lizardite and kaolinite), is reported. In a set of DFT methods following functionals were included: standard local and semi-local (LDA, PW91, PBE, and RPBE), dispersion corrected (PW91-D2, PBE-D2, RPBE-D2, and vdW-TS), and functionals developed specifically for solids and solid surfaces (PBEsol and AM05). We have shown that the standard DFT functionals fail in the correct prediction of the structural parameters, for which non-bonding interactions are important. The remarkable improvement leading to very good agreement with experimental structures is achieved if the dispersion corrections are included in the DFT calculations. In such cases the relative error for the most sensitive lattice vector c dropped below 1%. Very good performance was also observed for both DFT functionals developed for solids. Especially, the results achieved with the PBEsol are qualitatively similar to those with DFT-D2.

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Section: Introductionmentioning

confidence: 99%

Assessment of ten DFT methods in predicting structures of sheet silicates: Importance of dispersion corrections

Tunega

Bučko

Zaoui

2012

The Journal of Chemical Physics

122

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“…Pure kaolinite exhibits complex infrared and Raman spectra of which the four hydroxyl groups stretching bands receive particular attention. These bands have the highest frequencies (3,695,3,667,3,650, and 3,619 cm À1 ) of the spectrum [2] and are resolved enough to allow analysis of small perturbations caused by the intercalated molecules. The IR spectrum of pure kaolinite has already been the subject of theoretical studies.…”

Section: Introductionmentioning

confidence: 99%

Theoretical estimates of the IR spectrum of formamide intercalated into kaolinite

Campos

Filho

2011

Int J of Quantum Chemistry

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Calculations at PM3 and PBE/6-31G levels of part of the IR spectrum of the formamide-kaolinite intercalatation compound based on a 110-atom cluster of kaolinite with one formamide molecule are reported. Frequencies and intensities for the formamide vibrations and stretchings of four cluster hydroxyls were calculated through partial hessian matrices and polar tensors obtained by numerical differentiation of energy gradients and dipole moment. The formamide molecule attaches to the kaolinite inner surfaces in multiple conformations with its CN bond vector parallel to the surfaces. Hydrogen bonds are formed between the formamide hydrogen atoms (both from NH 2 or CH groups) and the siloxane surface and between the formamide oxygen and nitrogen atoms and the aluminol hydroxyls. The general features of the experimental assignment of the spectrum are confirmed, but the observed splitting of formamide bands is attributed to vibrations from differently attached molecules.

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“…Edge-edge (E-E), edge-face (E-F) and face-face (F-F) model aggregate structures had long been suggested by Lambe and van Olphen (Lambe, 1953;Olphen, 1977). It was apparently that the aggregate structures are dominating the final sediment density, with F-F interaction would produce denser settled bed than E-E and E-F interactions (Castro and Martins, 2005;Nasser and James, 2006).…”

Section: Introductionmentioning

confidence: 92%