Clays and Clay Minerals, Vol. 58, No. 1, 52–61, 2010.
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Authors
Smrcok, L’ubomir
Tunega, Daniel
Ramirez-cuesta, Anibal Javier
Ivanov, Alexander
Valuchova, Jana
Issue Date
2010
Type
Article
Language
Keywords
Periodicals , Geology , DFT , DMSO , Hydrogen Bonds , INS , Kaolinite , Vibrational Spectra
Alternative Title
The Combined Inelastic Neutron Scattering (ins) And Solid-state Dft Study Of Hydrogen-atoms Dynamics In Kaolinitedimethylsulfoxide Intercalate
Abstract
Vibrational spectra of two kaolinite-dimethylsulfoxide intercalates, obtained using inelastic neutron scattering (INS), were analyzed with a view to understanding the dynamics of the hydrogen atoms in the structure. The main focus was on the spectral region 0-1700 cm-1, which is difficult to analyze using optical spectroscopy. The experimental vibrational spectra of kaolinite:dimethylsulfoxide and kaolinite:d6-dimethylsulfoxide collected using two different spectrometers were interpreted by means of the solid-state DFT calculations. Calculated spectra were obtained by both normal-mode analysis and molecular dynamics going beyond the harmonic approximation. The Al-O-H bending modes were found to be spread over the large interval 100-1200 cm-1, with the dominant contributions located between 800 and 1200 cm-1. The shape of the individual hydrogen spectrum depends on whether or not the respective hydrogen atom is involved in an O-H_O hydrogen bond and on its strength. The modes corresponding to the in-plane movements of the inner-surface hydrogen atoms are well defined and always appear at the top of the intervals of energy transfer. In contrast, the modes generated by the out-of-plane movements of the hydrogen atoms are spread over large energy intervals extending down to the region of external (lattice) modes. The C-H modes are concentrated mainly in the three regions 1200-1450 cm-1, 800-1100 cm-1, and 0-400 cm-1. While the first two regions are typical of the various deformational modes of methyl groups, the low-energy region is populated by the modes corresponding to the movements of the whole dimethylsulfoxide molecule.
Description
gsccm58105-smr.pdf : 729KB
Citation
Clays and Clay Minerals, Vol. 58, No. 1, 52–61, 2010.
Publisher
The Clay Minerals Society
License
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