Abstract
The dynamics of the hydrogen atoms in the highly ordered kaolinite was studied by vibrational spectroscopy based on inelastic neutron scattering method with the focus on the spectral region of 100-1,250 cm-1. The experimental spectrum was interpreted by means of the solid state density functional theory calculations covering 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 of 100-1,100 cm-1, with the dominant contributions located between 800 and 1,100 cm-1. The shapes of the individual hydrogen spectra depend on the strengths of the individual interlayer O-H···O hydrogen bonds involving the inner surface hydroxyl groups. The modes assigned to the in-plane movements of the respective hydrogen atoms are well-defined and always appear on the top of the intervals of energy transfer. In contrast, the modes generated by the out-of-plane movements are spread over large intervals of energies spanning down to the region of external (lattice) modes.
Original language | English |
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Pages (from-to) | 571-579 |
Number of pages | 9 |
Journal | Physics and Chemistry of Minerals |
Volume | 37 |
Issue number | 8 |
DOIs | |
State | Published - 2010 |
Externally published | Yes |
Funding
The STFC ISIS Facility is acknowledged for providing neutron beam access on the TOSCA instrument. The authors acknowledge the financial support of the Slovak Research and Development Agency APVV under the contract APVV-51-050505 and of the Slovak Grant Agency VEGA under the contract 2/0150/09. This work has also benefited from the Centers of Excellence program of the Slovak Academy of Sciences (COMCHEM, Contract no. II/1/2007). One of us (D.T.) thanks to the German Research Foundation, priority program SPP 1315, Project GE 1676/1-1.
Keywords
- DFT
- Hydrogen bonds
- Inelastic neutron scattering
- Kaolinite
- Vibrational spectra