Crystallization of amorphous silica under compression

Nhan, Nguyen Thu; Trang, Giap Thi Thuy; Iitaka, Toshiaki; Hong, Nguyen Van

doi:10.1139/cjp-2018-0432

Cited by 9 publications

(3 citation statements)

References 31 publications

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“…158,166,167 Nonetheless, coupling between the Si-O-Si bond angle and the Si-O stretch force constant may not be as simple as the trigonometric function assumed in these non-central force constant models (see Section 6). [168][169][170][171] If the Si-O-Si bond angle influences the Si-O-Si stretch mode through the non-central force constant, why does it not affect the Si-O-Si bending mode at all in IR spectra of glass? No thorough discussion on this question could be found in the literature.…”

Section: Classical Models Of Solving Equations Of Motion For Small Clustersmentioning

confidence: 99%

Vibrational spectroscopy analysis of silica and silicate glass networks

et al. 2021

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Vibrational spectroscopy has been widely used to investigate various structural aspects of the glass network, and there are a plethora of papers reporting subtle but consistent changes in infrared and Raman spectral features of glass upon alterations of glass compositions, thermal histories, mechanical stresses, or surface treatments. However, interpretations of such spectral features are still obscured due to the lack of well-established physical principles accurately describing vibrational modes of the non-crystalline glass network. Due to the non-equilibrium nature of the glass network, three-dimensionally connected without any long-range orders, vibrational spectral features of glass cannot be interpreted using the analogy with those of isolated molecular moieties or crystalline counterparts. This feature article explains why such comparisons are outdated and describes the recent advances made from theoretical calculations of vibrational spectral features of amorphous networks or comparisons of computational results with experimental data. For the interpretation of vibrational spectral features of silica and silicate glasses, the following empirical relationships are suggested: (i) the intensity-weighted peak position of the Si-O-Si stretch mode negatively correlates with the weighted average of the Si-O bond length distribution, and (ii) the broad band of the Si-O-Si bending mode negatively correlates with the Si-O-Si bond angle distribution. Selected examples of vibrational spectroscopic imaging of surface defects are discussed to deliberate the implication of these findings in the structure-property relationship of silica and silicate glass materials. Unanswered questions and continuing research challenges are identified.

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Section: Classical Models Of Solving Equations Of Motion For Small Clustersmentioning

confidence: 99%

Vibrational spectroscopy analysis of silica and silicate glass networks

et al. 2021

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“…The relevant snapshots are shown in Figure 4. This issue also has been clarified by Nhan et al, [28]. The mean bond length of Si-O in SiO6 unit is longer than the one in SiO5, and the one in SiO4 is the shortest one, while the numbers of SiO6 and SiO5 units increase under compression.…”

Section: Methodsmentioning

confidence: 81%

Pressure-induced Glassy Networks of Enstatite (MgSiO3) and Forsterite (Mg2SiO4)

Anh

Nguyen²,

Hong

2023

MaP

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This work is designed to focus on the glassy network analysis and visualizing the cluster and subnets formation, the rich set of bond-, edge- and face-sharing linkages. The correlation between the degree of polymerization and linkages forming is apparently indicated. The distribution of SiOx clusters is computed to determine the polymerization characteristic and Mg-rich region. The distribution of BOs, NBOs and FOs also are investigated to prove the behavior of Mg2+ incorporating into the -Si-O- network. Polyhedral units, clusters, and subnets are vividly visualized so as to have a better understanding of cluster merging. Besides, in this work we have also clarified the distribution of edge-sharing and face-sharing subnets/network between Si-Si and Mg-Si species.

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“…The average Si-Si distance of corner-, edge-and face-sharing bonds are around 3.10, 2.80 and 2.55 Å, respectively. The existence of the corner-, edge-and face-sharing bonds with different bond length is the origin of the first peak splitting of Si-Si PRDF [44]. The Mg ions tend incorporate into -Si-O-glassy network via NBOs (at low pressure) and via both NBOs and BOs (at high pressure).…”

Section: Discussionmentioning

confidence: 99%

Topology of SiO_x-units and glassy network of magnesium silicate glass under densification: correlation between radial distribution function and bond angle distribution

Nguyen¹,

Anh²,

Kien³

et al. 2020

Modelling Simul. Mater. Sci. Eng.

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Topology of SiOx units and glassy network of magnesium silicate glass at different pressures are investigated by molecular dynamics simulation to clarify its microstructure under compression. Results show that SiOx-topology and glassy network structure are significantly dependent on pressure. At ambient pressure, the –Si–O– glassy network in Mg2SiO4 glass is split into subnets/clusters. Under compression, the small subnets tend to merge each other forming larger ones. The decrease of Si–O–Si bond angle under compression that accompanies a formation of edge- and face-sharing bonds between SiOx units results in the first peak splitting of Si–Si PRDF at high pressure. In particular, the investigation also reveals a tight correlation between PRDFs (Si–Si, Mg–Mg, Si–Mg, O–O) and BADs (Si–O–Si, Mg–O–Mg, Mg–O–Si, O–T–O (T = Si, Mg)), respectively. The spatial distribution of corner-, edge- and face-sharing bonds is not uniform but forming subnets/clusters. The clusters of face-sharing bonds form rigid particles embedding into mixture clusters of corner- and edge-sharing bonds. Size distribution of subnets/clusters (SiOx-cluster as well as clusters of corner-, edge- and face-sharing bonds) under compression also has been investigated to clarify the intermediate range order. The characteristic change of PRDFs under compression in the relationship with microstructural change and the mechanism of magnesium ions incorporation into –Si–O– network is also discussed in detail.

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Crystallization of amorphous silica under compression

Cited by 9 publications

References 31 publications

Vibrational spectroscopy analysis of silica and silicate glass networks

Vibrational spectroscopy analysis of silica and silicate glass networks

Pressure-induced Glassy Networks of Enstatite (MgSiO3) and Forsterite (Mg2SiO4)

Topology of SiO_x-units and glassy network of magnesium silicate glass under densification: correlation between radial distribution function and bond angle distribution

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Crystallization of amorphous silica under compression

Cited by 9 publications

References 31 publications

Vibrational spectroscopy analysis of silica and silicate glass networks

Vibrational spectroscopy analysis of silica and silicate glass networks

Pressure-induced Glassy Networks of Enstatite (MgSiO3) and Forsterite (Mg2SiO4)

Topology of SiO x -units and glassy network of magnesium silicate glass under densification: correlation between radial distribution function and bond angle distribution

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Topology of SiO_x-units and glassy network of magnesium silicate glass under densification: correlation between radial distribution function and bond angle distribution