Clays and Clay Minerals, Vol. 58, No. 1, 89–96, 2010.
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Authors
Liu, Xiandong
Meijer, Evert Jan
Lu, Xiancai
Wang, Rucheng
Issue Date
2010
Type
Article
Language
Keywords
Periodicals , Geology , CPMD , Density Functional Theory , Hydroxyl Orientation , Iron , Smectite , Vibration Dynamics
Alternative Title
Ab Initio Molecular Dynamics Study Of Fe-containing Smectites
Abstract
In order to identify the influences imposed by Fe substitution, density functional theory-based Car-Parrinello molecular dynamics simulations were employed to study both oxidized and reduced Febearing smectites. The following basic properties were investigated: local structures in the clay layer, hydroxyl orientations, and the vibration dynamics of H and Si. Structural analyses indicated that the average Fe-O bond lengths are ~2.08 A ˚ and 2.02 A ˚ in the reduced and oxidized models, respectively, and the Fe substitutions did not affect the coordination structures of the Al-O and Si-O polyhedra. For hydroxyl orientations, Fe(III) substitution had no obvious influence but Fe(II) forces the coordinated hydroxyls to present a wide-angle distribution. Furthermore, the present work has shown that both substitutions can red-shift the hydroxyl in-plane bending mode. The analyses also revealed that Fe(III) substitution has no effect on the Si-O stretching, while Fe reduction causes a blue-shift of the out-of-plane stretching mode. The results provide quantitative constraints and clues for future research.
Description
gsccm58109-liu.pdf : 1,380KB
Citation
Clays and Clay Minerals, Vol. 58, No. 1, 89–96, 2010.
Publisher
The Clay Minerals Society
License
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