Insight into the structure of vanadium containing glasses: A molecular dynamics study

Ori, Guido; Montorsi, Monia; Pedone, Alfonso; Siligardi, Cristina

doi:10.1016/j.jnoncrysol.2011.02.002

Cited by 42 publications

(23 citation statements)

References 88 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…This ratio should stay relatively insensitive to the total vanadium content as observed by Farah and Brungs (2003), and V 5+ should be the predominant species (> 86%) in all glasses. DiAn composition is in agreement with experimental data previously reported (Giuli et al, 2004) and with molecular dynamic simulations (Ori et al, 2011). Similarly, in the NAS ternary system, according to Leister et al (1999), Al-free sodium silicate glasses, synthesized in air, should have ∼96% of V 5+ .…”

Section: Resultssupporting

confidence: 91%

Influence of Vanadium on Optical and Mechanical Properties of Aluminosilicate Glasses

Cicconi¹,

Lu²,

Uesbeck

et al. 2020

Front. Mater.

View full text Add to dashboard Cite

V 2 O 5 was introduced up to 9 wt.% in a peralkaline alkaline earth aluminosilicate glass and up to 4.8 wt.% in two sodo aluminosilicate glasses, respectively, a peralkaline and a peraluminous one. This introduction had a strong effect on thermal properties, and in particular, on glass transition and crystallization temperatures of the peraluminous glass, which dropped by 89 K, while a moderate drop of ∼20 K was observed for the two other glasses. Still, the glass stability and the glass-forming ability stayed almost unmodified. The elastic properties measured by Brillouin spectroscopy show a decrease with added Vanadium for the depolymerized alkali earth aluminosilicate and the peraluminous sodo aluminosilicate. In contrast, the elastic properties remained unchanged for the peralkaline composition. Using optical absorption, the proportion of V 5+ , which is largely dominant, was found to follow the trend predicted using optical basicity considerations. A large photoluminescence emission, centered at ∼560 nm, was found for all glasses, upon excitation in the UV edge at both ∼280 and ∼350 nm. The emission band positions were relatively insensitive to the glass composition, whereas their intensities show variations of one order of magnitude between the sodium peralkaline composition and the calcium depolymerized glass. A too-high concentration of V 2 O 5 shows a quenching effect on the emission. Polarized and cross-polarized Raman spectroscopy allowed us to identify the different environments around the V 5+ O 4 tetrahedra. The highly polarizable V 5+ O 4 tetrahedra associated with two non-bridging oxygens, vibrating at 860 cm −1 , is proposed to be responsible for the more efficient charge transfer. At the opposite end, the formation of VO 4 -AlO 4 units is proposed to quench luminescence properties. Furthermore, we observed that, upon thermal treatment, the optical properties of the glasses are significantly modified without observable structural modifications or evolution of the elastic properties.

show abstract

Section: Resultssupporting

confidence: 91%

Influence of Vanadium on Optical and Mechanical Properties of Aluminosilicate Glasses

Cicconi¹,

Lu²,

Uesbeck

et al. 2020

Front. Mater.

View full text Add to dashboard Cite

show abstract

“…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][32][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: Computational Detailsmentioning

confidence: 86%

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

2012

Self Cite

View full text Add to dashboard Cite

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.

show abstract

“…In particular, a detailed structure analysis by small angle neutron/X-ray diffraction techniques and molecular dynamic modeling will provide additional information on the role of the structure in determining the properties of the vanadium tellurite glass systems. 53,54 a R is the mean distance between vanadium ions (from density data and eq 4), and c is the ratio of V 4+ to total vanadium (from EPR measurements). …”

Section: Discussionmentioning

confidence: 99%

Critical V₂O₅/TeO₂Ratio Inducing Abrupt Property Changes in Vanadium Tellurite Glasses

Kjeldsen¹,

Rodrigues²,

Mossin³

et al. 2014

J. Phys. Chem. B

View full text Add to dashboard Cite

Transition metal containing glasses have unique electrical properties and are therefore often used for electrochemical applications, such as in batteries. Among oxide glasses, vanadium tellurite glasses exhibit the highest electronic conductivity and thus the high potential for applications. In this work, we investigate how the dynamic and physical properties vary with composition in the vanadium tellurite system. The results show that there exists a critical V(2)O(5) concentration of 45 mol %, above which the local structure is subjected to a drastic change with increasing V(2)O(5), leading to abrupt changes in both hardness and liquid fragility. Electronic conductivity does not follow the expected correlation to the valence state of the vanadium as predicted by the Mott-Austin equation but shows a linear correlation to the mean distance between vanadium ions. These findings could contribute to designing optimum vanadium tellurite compositions for electrochemical devices. The work gives insight into the mechanism of electron conduction in the vanadium tellurite systems.

show abstract

Insight into the structure of vanadium containing glasses: A molecular dynamics study

Cited by 42 publications

References 88 publications

Influence of Vanadium on Optical and Mechanical Properties of Aluminosilicate Glasses

Influence of Vanadium on Optical and Mechanical Properties of Aluminosilicate Glasses

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

Critical V₂O₅/TeO₂Ratio Inducing Abrupt Property Changes in Vanadium Tellurite Glasses

Contact Info

Product

Resources

About

Insight into the structure of vanadium containing glasses: A molecular dynamics study

Cited by 42 publications

References 88 publications

Influence of Vanadium on Optical and Mechanical Properties of Aluminosilicate Glasses

Influence of Vanadium on Optical and Mechanical Properties of Aluminosilicate Glasses

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

Critical V2O5/TeO2Ratio Inducing Abrupt Property Changes in Vanadium Tellurite Glasses

Contact Info

Product

Resources

About

Critical V₂O₅/TeO₂Ratio Inducing Abrupt Property Changes in Vanadium Tellurite Glasses