An infrared spectroscopic study of water-related species in silica glasses

Davis, Ken; Tomozawa, M.

doi:10.1016/0022-3093(95)00631-1

Cited by 369 publications

(347 citation statements)

References 43 publications

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“…2 The XRD profiles for bleached sample and silica gel, and heated samples. Solid circle is the peak of cristobalite (Graetsch 1994) the superposition of the several bands of O-H stretching vibration of water molecules and silanol groups (Anedda et al 2003;Davis and Tomozawa 1996). A band attributed to the Si-OH stretching vibration of silanol (Kamiya et al 2000) is clearly observed at ν = 950 cm −1 in the spectrum for silica gel used in this study.…”

Section: Atr-ir Spectroscopic Analysismentioning

confidence: 74%

Structural change of the frustule of diatom by thermal treatment

Arasuna

Okuno

2018

Geosci. Lett.

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The external skeleton, frustule, of a diatom is composed of hydrous amorphous silica and amino acids. In this study, the structural changes in the frustule of Chaetoceros calcitrans after thermal treatment up to 1200 °C were investigated using X-ray diffraction and attenuated total reflection infrared spectroscopy and Raman spectroscopy. Their structural changes after thermal treatment give important information to elucidate the unheated structure of the frustule and its crystallization process. In addition, this study is almost the first report to discuss the structure of diatom frustule in detail with Raman spectrum. The unheated structure of the frustule has the relatively ordered and dominant sixmembered ring structure made of SiO 4 tetrahedra. The sample heated at 800 °C has the more ordered six-membered ring structure observed in quartz or cristobalite. Water molecules and silanol (Si-OH) included in the frustule are dehydrated at this temperature. This dehydration may promote the formation of ordered and polymerized structure. The structure of the frustule after heating at 1200 °C is similar to that of low-cristobalite. However, additional heating is required for complete crystallization.

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Section: Atr-ir Spectroscopic Analysismentioning

confidence: 74%

Structural change of the frustule of diatom by thermal treatment

Arasuna

Okuno

2018

Geosci. Lett.

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“…Experimental methods such as infrared spectroscopy, [3][4][5] x-ray crystallography, 6,7 nuclear magnetic resonance, 8 and electron microscopy do not sufficiently describe the processes by which silica is corroded by water at an atomic scale. 9 Molecular dynamics ͑MD͒ techniques, due to their ability to probe nanoscale spatiotemporal processes, can provide valuable insights into this problem.…”

Section: Introductionmentioning

confidence: 99%

A reactive molecular dynamics simulation of the silica-water interface

Fogarty

Aktulga

Grama

et al. 2010

The Journal of Chemical Physics

468

458

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We report our study of a silica-water interface using reactive molecular dynamics. This first-of-its-kind simulation achieves length and time scales required to investigate the detailed chemistry of the system. Our molecular dynamics approach is based on the ReaxFF force field of van Duin et al. ͓J. Phys. Chem. A 107, 3803 ͑2003͔͒. The specific ReaxFF implementation ͑SERIALREAX͒ and force fields are first validated on structural properties of pure silica and water systems. Chemical reactions between reactive water and dangling bonds on a freshly cut silica surface are analyzed by studying changing chemical composition at the interface. In our simulations, reactions involving silanol groups reach chemical equilibrium in ϳ250 ps. It is observed that water molecules penetrate a silica film through a proton-transfer process we call "hydrogen hopping," which is similar to the Grotthuss mechanism. In this process, hydrogen atoms pass through the film by associating and dissociating with oxygen atoms within bulk silica, as opposed to diffusion of intact water molecules. The effective diffusion constant for this process, taken to be that of hydrogen atoms within silica, is calculated to be 1.68ϫ 10 −6 cm 2 / s. Polarization of water molecules in proximity of the silica surface is also observed. The subsequent alignment of dipoles leads to an electric potential difference of ϳ10.5 V between the silica slab and water.

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“…11,12 In each of these applications, the role of water and how it changes the properties of silica are important features, and the interaction between silica and water has attracted considerable attention. [13][14][15][16][17][18][19][20][21] Water weathers and dissolves the Earth's crust silicate mineral. It is present during quartz nucleation, and thus influences its crystal strength and growth rate.…”

Section: Introductionmentioning

confidence: 99%

“…Silica glass exhibits static fatigue in humid environments 22 or with the incorporation of small amounts of water into the glass. 23 Silanol groups ͑Si-O-H͒ have been detected on silica surfaces by experiments, [13][14][15] but it is very difficult to deduce how water dissociates on the silica surface and how these silanols are formed 13 A powerful method for understanding the hydrolysis process is molecular dynamics ͑MD͒ simulation. However, to describe the chemical bonds and reaction dynamics accurately this needs to be performed using a quantummechanical treatment.…”

Section: Introductionmentioning

confidence: 99%

Reactions and clustering of water with silica surface

Foster

Nieminen

2005

The Journal of Chemical Physics

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A quantum mechanical study of the reactivity of ( Si O ) 2 -defective silica surfaces J. Chem. Phys. 128, 204702 (2008) The interaction between silica surface and water is an important topic in geophysics and materials science, yet little is known about the reaction process. In this study we use first-principles molecular dynamics to simulate the hydrolysis process of silica surface using large cluster models. We find that a single water molecule is stable near the surface but can easily dissociate at three-coordinated silicon atom defect sites in the presence of other water molecules. These extra molecules provide a mechanism for hydrogen transfer from the original water molecule, hence catalyzing the reaction. The two-coordinated silicon atom is inert to the water molecule, and water clusters up to pentamer could be stably adsorbed at this site at room temperature.

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An infrared spectroscopic study of water-related species in silica glasses

Cited by 369 publications

References 43 publications

Structural change of the frustule of diatom by thermal treatment

Structural change of the frustule of diatom by thermal treatment

A reactive molecular dynamics simulation of the silica-water interface

Reactions and clustering of water with silica surface

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