Molecular dynamics study of temperature dependence of volume of amorphous silica

Kuzuu, Nobu; Yoshie, Hiroki; Tamai, Yoshinori; Wang, Chen

doi:10.1016/j.jnoncrysol.2004.08.207

Cited by 21 publications

(43 citation statements)

References 19 publications

(28 reference statements)

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“…FTIR spectra showed that the Si–O–Si bond angle decreased with increasing temperature from 1000°C to 1500°C, thus the density increased with increasing temperature . A similar behavior was observed in molecular dynamics (MD) simulation, which indicated the decreased Si–O–Si bond angle, corresponding to the decreased Si–Si distance with increasing temperature . In addition, 5‐coordinated Si ( 5 Si) was also proposed as a possible structural origin of the density maximum in silica glass, because its concentration exhibited a maximum around the temperature at which the density maximum occurred in MD simulations …”

Section: Introductionsupporting

confidence: 55%

Structural origin of the anomalous density maximum in silica and alkali silicate glasses

2019

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Silica, sharing the same tetrahedral order and many structural, thermodynamic and dynamic anomalies with water, has been speculated to have a density increase upon melting similar to water. In this work, an increase in density upon melting cristobalite silica and a shallow density maximum followed by a density minimum during cooling of silica liquid are observed in classical molecular dynamics simulations. The density maximum gradually diminishes with the increase in alkali size/content in alkali silicate glasses. The structural origin of the anomalous density maximum in silica is revealed by detailed structural analysis. During the cooling process, a range of rings with different sizes form in liquid silica, with 6-member rings being the most dominant, which cause the silica network to open up and compensate the regular volume shrinkage upon cooling. These two competing factors lead to a density maximum, but to a less extent than that observed in melting of cristobalite silica. With the increase in modifier size/content in the alkali silicate glasses, the connectivity of silica network gradually breaks down; the population of 6-member rings decrease with the increase in smaller or larger rings, therefore the density maximum becomes less obvious and eventually disappears. K E Y W O R D Satomistic simulation, density maximum, silica, silicates

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Section: Introductionsupporting

confidence: 55%

Structural origin of the anomalous density maximum in silica and alkali silicate glasses

2019

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“…In a simulation study for bulk vitreous silica using a pair-additive potential with the Morse and exact Coulomb interaction terms, a peak at 160 and a trace of a shoulder at 140 were observed. 19) In the present case, the bond-angle distribution is complex. As previously pointed out, the peak at 100 is due to the edge-share structure.…”

Section: Bond-angle Distributionmentioning

confidence: 73%

“…In fact, the results of the molecular dynamics simulations of bulk vitreous silica using various types of potential reveal a unique peak at the tetrahedral angle. 19) However, near the surface, the distribution differs from the regular distribution with a unique peak (Fig. 8).…”

Section: Bond-angle Distributionmentioning

confidence: 92%

“…Potentials containing the three-body term cannot reproduce the structure at high temperatures. 19) The volume-temperature curve of the vitreous silica has a minimum at a high temperature, 1) which can be reproduced only when pair-additive potentials are used. 19) This is because the three-body term acts as a repulsion force at high temperatures.…”

Section: Introductionmentioning

confidence: 99%

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Molecular Dynamic Study on Structure of Interface Formed by Binding Flat Amorphous Silica Surfaces at High Temperatures

Kuzuu

Nagai

Tanaka

et al. 2005

Jpn. J. Appl. Phys.

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The structure of the interface formed by the binding of flat amorphous silica (a-SiO 2 ) surfaces at high temperatures was investigated by molecular dynamics simulation. The surface before binding was formed by the same method as that previously used for studying the a-SiO 2 surface [J. Appl. Phys. 92 (2002) 4408], in which a slab of silica sandwiched by two vacuum regions is used as the unit cell under three-dimensional periodic boundary conditions. The surfaces were contacted by reducing the cell size along the vacuum-sandwiched direction progressively up to the size of the simulation cell being the same as that of the bulk silica. The system was then heated at high temperatures up to 3000 K and quenched to 300 K. Although the coordination numbers of almost all atoms are regular, that is, four for Si and two for O, at temperatures higher than 2500 K, the density of the interface remained lower than that of the bulk region.

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“…The V-T dependence of v-SiO 2 can be reproduced by molecular dynamics (MD) simulation. [4][5][6] Perchack and O'Reilly 4) reproduced the volume minimum using the pairadditive potential with a screened Coulomb term. 7) In their results, the volume-temperature curve depends on cooling and heating rates, and the parameters using pressure control.…”

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confidence: 99%

Molecular Dynamics Study of Compressibility of Vitreous Silica

Kuzuu

Nagai

Tanaka

et al. 2005

Jpn. J. Appl. Phys.

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The temperature dependence of the isothermal compressibility of vitreous silica has been studied by molecular dynamics simulation. The compressibility discontinuously jumps from %2 Â 10 À11 to %6 Â 10 À11 Pa À1 with a change in temperature up to %3200 K at which the thermal expansivity changes from positive to negative. The compressibility values were on the same order as that obtained by the light scattering experiment in the literature reported previously.

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Molecular dynamics study of temperature dependence of volume of amorphous silica

Cited by 21 publications

References 19 publications

Structural origin of the anomalous density maximum in silica and alkali silicate glasses

Structural origin of the anomalous density maximum in silica and alkali silicate glasses

Molecular Dynamic Study on Structure of Interface Formed by Binding Flat Amorphous Silica Surfaces at High Temperatures

Molecular Dynamics Study of Compressibility of Vitreous Silica

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