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- Belonoshko, Anatoly B., et al.
(författare)
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Molecular dynamics simulation of the structure of yttria Y2O3 phases using pairwise interactions
- 2001
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Ingår i: Physical Review B Condensed Matter. - 0163-1829 .- 1095-3795. ; 6418:18
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Tidskriftsartikel (refereegranskat)abstract
- We have studied the structure of yttria (Y2O3) by means of ab initio and molecular dynamics methods. The suggested simple model for the interatomic interaction is shown to produce reasonable results at moderate pressures for a wide range of temperatures. The calculated x-ray structure factor is in good agreement with experimental data obtained by the x-ray levitation technique at the temperature of 2526 K. The quality of the agreement decreases with increasing temperature. We demonstrate that it is not necessary to assume nonstoichiometry of liquid yttria, as was done in a recent publication, to obtain agreement with experiment. The structure of liquid yttria can be considered as a mixture of 4- and 6-coordinated Y atoms. We also show the possibility of a light amorphous yttria phase, which possibly can be obtained by quenching from a vapor instead of conventional amorphous yttria quenched from a liquid.
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- Gutierrez, G., et al.
(författare)
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Structural properties of liquid Al2O3 : A molecular dynamics study
- 2000
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Ingår i: Physical Review E. Statistical, Nonlinear, and Soft Matter Physics. - 1063-651X .- 1095-3787. ; 61:3, s. 2723-2729
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Tidskriftsartikel (refereegranskat)abstract
- Molecular dynamics (MD) simulations of liquid aluminum oxide (Al2O3) were carried out on a system with up to 1800 particles, using a pairwise potential. All simulations were done in the microcanonical ensemble, for two densities, 3.0 and 3.175 g/cm(3), at temperatures of 2200, 2600, and 3000 K. A detailed analysis of the interatomic distances, given by the partial pair-distribution functions and the bond-angles distribution, reveals that in the liquid state there is st short range order dominated by a somewhat distorted (AlO4)(5-) tetrahedron, in agreement with recent experimental measurements. This conclusion is supported by the distribution of nearest-neighbor coordinations, where more than 60% of Al atoms have four O as nearest neighbors. This finding does not change over the explored temperature range. Because of the presence of twofold rings, the connectivity of (AlO4)(5-) units consists of corner, edge, and face sharing tetrahedra. Based in this structural information, i.e., bond lengths, coordination numbers, bond-angle distributions, and ring statistics, our MD simulation allows us to put forward a possible structure of liquid Al2O3.
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- Gutierrez, G, et al.
(författare)
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Structural properties of liquid Al2O3: A molecular dynamics study
- 2000
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Ingår i: PHYSICAL REVIEW E. - : AMERICAN PHYSICAL SOC. - 1063-651X. ; 61:3, s. 2723-2729
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Tidskriftsartikel (refereegranskat)abstract
- Molecular dynamics (MD) simulations of liquid aluminum oxide (Al2O3) were carried out on a system with up to 1800 particles, using a pairwise potential. All simulations were done in the microcanonical ensemble, for two densities, 3.0 and 3.175 g/cm(3), at
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