Molecular dynamics simulations of sodium silicate glasses: Optimization and limits of the computational procedure

Pota, Marco; Pedone, Alfonso; Malavasi, Gianluca; Durante, Caterina; Cocchi, Marina; Menziani, Maria Cristina

doi:10.1016/j.commatsci.2009.10.017

Cited by 28 publications

(24 citation statements)

References 38 publications

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“…The high amount of TBO found in our models is in agreement with Car-Parrinello MD simulations [40], suggesting that their presence might be a consequence of the small system sizes and the very fast quenching rate that we are forced to use in our computational investigations [2,41] but inaccuracies due to the empirical force field employed cannot be excluded.…”

Section: Resultssupporting

confidence: 83%

First-principles simulations of the 27Al and 17O solid-state NMR spectra of the CaAl2Si3O10 glass

et al. 2012

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The local and medium-range structure of the 20CaO·20Al2O3·60SiO2 glass generated by classical molecular dynamics simulations has been compared to NMR experiments by computing the 27Al and 17O NMR parameters and NMR spectra from first-principles simulations. The calculation of the NMR parameters (chemical shielding and quadrupolar parameters), which are then used to simulate solid-state MAS and 3QMAS NMR spectra, is achieved by the gauge including projector augmented-wave and the projector augmented-wave methods on the DFT-PBE relaxed structure. The NMR spectra calculated with the present approach are found to be in excellent agreement with the experimental data, providing an unambiguous view of the local and medium-range structure of aluminosilicate glasses

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Section: Resultssupporting

confidence: 83%

First-principles simulations of the 27Al and 17O solid-state NMR spectra of the CaAl2Si3O10 glass

et al. 2012

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“…This suggests that more care may be required in the melting procedure that is used to form the glasses. In a recent study [15] suggesting optimized controls for molecular dynamics systems, the subject of system size was left largely unaddressed. The decreasing configurational energy noted with increasing system size indicates that the structure is able to relax more fully as the periodic boundary constraints are moved further out.…”

Section: Discussionmentioning

confidence: 99%

Large-scale simulations of sodium silicate glasses

Adkins

Cormack

2011

Journal of Non-Crystalline Solids

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“…14 The final structures were obtained by using CPMD simulations in the framework of the melt-quench approach. 18,[25][26][27][28][29][30] It is worth noting that, albeit the small scale of ab initio models prevents a detailed study of the medium-range-structure, the relatively small size of the models employed in the present work was demonstrated to be adequate to study the local structure, such as the coordination environment of ions in bioactive glasses, important vibrational features 19,31-33 and NMR parameters. 23,34,35 NMR calculations were carried out by means of the CASTEP 36 density functional theory (DFT) code using the GIPAW 20 algorithm, which allows the reconstruction of the allelectron wave function in the presence of a magnetic field.…”

Section: Experimental Section Computational Detailsmentioning

confidence: 94%

The structure of fluoride-containing bioactive glasses: new insights from first-principles calculations and solid state NMR spectroscopy

2012

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Fluoride-containing bioactive glasses are attracting particular interest in many fields of dentistry and orthopedics because they combine the bone-bonding ability of bioactive glasses with the anticariogenic protection provided by fluoride ions. Since the biomedical applications of these materials critically depend on the release of ionic species in the surrounding physiological environment, a deep knowledge of their environments is required. In this paper, density functional theory calculations and spin effective Hamiltonians have been employed to analyse the NMR signatures of the various environments of 19 F, 29 Si, 31 P and 23 Na atoms in fluorinated bioglasses structural models previously generated by CarParrinello molecular dynamics simulations. Comparison with experimental spectra expressly recorded in this work shows a good agreement and allows the enlightenment of some longstanding issues about the atomic structure of fluorinated bioglasses, such as the presence of Si-F and Si-O-P bonds. In particular, it is shown that Si-F bonds cannot be resolved by using MAS NMR experiments only, and 29 Si{ 19 F} REDOR experiments, that probes directly spatial proximities among atoms, must be employed. Our results show that F is coordinated entirely to the modifier ions Na and Ca, and that no Si-F bonds are present in the real glass structure. Thus, the addition of fluorine to the 45S5 BioglassÒ increases the polymerization of the silicate network by removing modifiers from the siliceous matrix and reducing its reactivity. Finally, the computed isotropic chemical shifts of the various environments of phosphorus show that, if present, Si-O-P bonds should be clearly noticeable in the 31 P static NMR experimental spectrum. Instead, the latter show that P is present as isolated orthophosphate units and does not enter into the siliceous matrix by forming Si-O-P bonds as conjectured by molecular dynamics simulations.

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Molecular dynamics simulations of sodium silicate glasses: Optimization and limits of the computational procedure

Cited by 28 publications

References 38 publications

First-principles simulations of the 27Al and 17O solid-state NMR spectra of the CaAl2Si3O10 glass

First-principles simulations of the 27Al and 17O solid-state NMR spectra of the CaAl2Si3O10 glass

Large-scale simulations of sodium silicate glasses

The structure of fluoride-containing bioactive glasses: new insights from first-principles calculations and solid state NMR spectroscopy

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