Determination of acoustic phonon dispersion curves in layer silicates by inelastic neutron scattering and computer simulation techniques

Collins, David R.; Stirling, W. G.; Catlow, C. Richard A.; Rowbotham, G.

doi:10.1007/bf00203052

Cited by 14 publications

(4 citation statements)

References 24 publications

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“…The maximum frequency in physical units is about 2.2 THz, which is larger than that obtained with molecular dynamics and neutron spectroscopy to be about 1.6 THz [24][25][26]. This is understandable due to the simplicity of our model considering just one type of atoms compared with the complexity of real mica, but it is within the same range of values.…”

Section: Phononsmentioning

confidence: 56%

Moving Excitations in Cation Lattices

et al. 2013

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We consider a model made out of identical particles that repel each other with the Coulomb interaction. We study numerically and analytically the existence and properties of supersonic kinks, showing that they are very easy to be produced and propagate long distances. They have a wide range of velocities and energies. We are motivated by a special characteristic of the muscovite mica mineral. Tracks from particles such as muons can be distinguished in a complex decoration, but the only explanation to most of the tracks is localized excitations called quodons. They move in the cation lattice, sandwiched between the silicate layers, along the lattice directions. Quodons have also been observed experimentally [EPL 78 (2007)

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Section: Phononsmentioning

confidence: 56%

Moving Excitations in Cation Lattices

et al. 2013

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“…3 we plot the dispersion curve as obtained for our model in physical units (left), and compare it with data obtained from neutron spectroscopy and molecular dynamics in Ref. [11] (right). We can see that there is a general agreement in the shape and values.…”

Section: Phononsmentioning

confidence: 99%

Supersonic Kinks in Coulomb Lattices

Archilla

Kosevich

Jiménez

et al. 2013

Nonlinear Systems and Complexity

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Summary. There exist in nature examples of lattices of elements for which the interaction is repulsive, the elements are kept in place because different reasons, as border conditions, geometry (e.g., circular) and, certainly, the interaction with other elements in the system, which provides an external potential. A primer example are layered silicates as mica muscovite, where the potassium ions form a two dimensional lattice between silicate layers. We propose an extremely simplified model of this layer in order to isolate the properties of a repulsive lattice and study them. We find that they are extremely well suited for the propagation of supersonic kinks and multikinks. Theoretically, they may have as much energy and travel as fast as desired. This striking results suggest that the properties of repulsive lattices may be related with some yet not fully explained direct and indirect observations of lattice excitations in muscovite.

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“…Until now, molecular simulations of clay interfaces have been limited to either static energy minimizations − or situations where the clay was fixed as a rigid lattice. − This approach has provided useful information about structures of solutions near the clay but has some inherent limitations. First, it is likely that motions of the clay surface atoms will influence the structure of the nearest water layers and the properties of solvated molecules and ions.…”

Section: Introductionmentioning

confidence: 99%

Molecular Dynamics Modeling of Clay Minerals. 1. Gibbsite, Kaolinite, Pyrophyllite, and Beidellite

et al. 1997

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A molecular dynamics model for clays and the oxide minerals is desirable for studying the kinetics and thermodynamics of adsorption processes. To this end, a valence force field for aluminous, dioctahedral clay minerals was developed. Novel aspects of this development include the bending potential for octahedral O−Al−O angles, which uses a quartic polynomial to create a double-well potential with minima at both 90° and 180°. Also, atomic point charges were derived from comparisons of ab initio molecular electrostatic potentials with X-ray diffraction-based deformation electron densities. Isothermal−isobaric molecular dynamics simulations of quartz, gibbsite, kaolinite, and pyrophyllite were used to refine the potential energy parameters. The resultant force field reproduced all the major structural parameters of these minerals to within 1% of their experimentally determined values. Transferability of the force field to simulations of adsorption onto clay mineral surfaces was tested through simulations of Na+, Ca2+, and hexadecyltrimethylammonium (HDTMA+) in the interlayers of beidellite clays. The new force field worked rather well with independently derived nonbonded parameters for all three adsorbates, as indicated by comparisons between experimental and molecular-dynamics-predicted d (001) layer spacings of the homoionic beidellites.

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Determination of acoustic phonon dispersion curves in layer silicates by inelastic neutron scattering and computer simulation techniques

Cited by 14 publications

References 24 publications

Moving Excitations in Cation Lattices

Moving Excitations in Cation Lattices

Supersonic Kinks in Coulomb Lattices

Molecular Dynamics Modeling of Clay Minerals. 1. Gibbsite, Kaolinite, Pyrophyllite, and Beidellite

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