Vibrational spectra in fluoride crystals and glasses at normal and high pressures by computer simulation

Boulard, B.; Kieffer, John; Phifer, Carol C.; Angell, C. Austen

doi:10.1016/s0022-3093(05)80795-1

Cited by 63 publications

(45 citation statements)

References 14 publications

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“…However, quantum chemical simulations suggest that zirconium clusters with high coordination states of 7 to 8 are favorable [33][34][35][36], in agreement with the coordination numbers determined by X-ray diffraction [37,38]. These high coordination numbers require the presence of double bridging/edge-sharing links.…”

Section: Structure Of Fluorozirconate Glasssupporting

confidence: 73%

“…The next Raman mode (≈ 480 cm −1 ) is assigned to the antisymmetric stretching vibration of the bridging fluorine bonds Zr-F B with no movement of the heavier zirconium atoms involved [40,41]. In compliance with the occurrence of edge sharing bonds, this band was assigned by Boulard et al to symmetric and antisymmetric stretching of the fluorine double bridging link [33]. Almeida et al assigned the 400 cm −1 and 330 cm −1 band to motion by the non-bridging/terminal fluorine F T , where the higher frequency band corresponds to an antisymmetric stretching and the lower frequency band to a possible 'umbrella' motion.…”

Section: Raman Spectra Of Fluorozirconate Glassmentioning

confidence: 87%

See 1 more Smart Citation

Femtosecond laser induced structural changes in fluorozirconate glass

Gross¹,

Lancaster²,

Ebendorff-Heidepriem³

et al. 2013

Opt. Mater. Express

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Section: Structure Of Fluorozirconate Glasssupporting

confidence: 73%

Section: Raman Spectra Of Fluorozirconate Glassmentioning

confidence: 87%

Femtosecond laser induced structural changes in fluorozirconate glass

Gross¹,

Lancaster²,

Ebendorff-Heidepriem³

et al. 2013

Opt. Mater. Express

View full text Add to dashboard Cite

“…Martinez-Gonzalez, English, and Gowen AIP Advances 7, 115105 (2017) that the calculated IR spectrum using the flux-flux autocorrelation function differs from IR spectrum obtained by the autocorrelation function only in its intensity 38 and, is less sensitive to the size of the sample to compute the IR, 42 we have used the latter formulation (flux-flux ACF) in the present study for calculating the IR spectrum.…”

Section: -5mentioning

confidence: 99%

Understanding the interface between silicon-based materials and water: Molecular-dynamics exploration of infrared spectra

2017

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Molecular-dynamics simulations for silicon, hydrogen-and hydroxyl-terminated silicon in contact with liquid water, at 220 and 300 K, display water-density 'ordering' along the laboratory z-axis, emphasising the hydrophobicity of the different systems and the position of this first adsorbed layer. Density of states (DOS) of the oxygen and proton velocity correlation functions (VACFs) and infrared (IR) spectra of the first monolayer of adsorbed water, calculated via Fourier transformation, indicate similarities to more confined, ice-like dynamical behaviour (redolent of ice). It was observed that good qualitative agreement is obtained between the DOS for this first layer in all systems. The DOS for the lower-frequency zone indicates that for the interface studied (i.e., the first layer near the surface), the water molecules try to organise in a similar form, and that this form is intermediate between liquid water and ice. For IR spectra, scrutiny of the position of the highest-intensity peaks for the stretching and bending bands indicate that such water molecules in the first solvating layer are organised in an intermediate fashion between ice and liquid water.

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“…This process has been followed spectroscopically in the cases of vitreous SiO2 and GeO2 (12). The hysteretically reversible spectral changes have been directly correlated with reversible coordination number changes in the glass by an ion dynamics computer simulation study of the spectral changes associated with polyamorphism in the analogous vitreous BeF2 system (21). The most careful computer simulation study of the phenomenon, that performed on vitreous ice (22), showed that the low-density amorphous state resists compression up to some critical pressure, which depends on the temperature, whereafter a rapid collapse to a high-density, highcoordination state is observed.…”

mentioning

confidence: 99%

The old problems of glass and the glass transition, and the many new twists.

Angell

1995

Proc. Natl. Acad. Sci. U.S.A.

154

134

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In this paper I review the ways in which the glassy state is obtained both in nature and in materials science and highlight a "new twist"-the recent recognition of polymorphism within the glassy state. The formation of glass by continuous cooling (viscous slowdown) is then examined, the strong/fragile liquids classification is reviewed, and a new twist-the possibility that the slowdown is a result of an avoided critical point-is noted. The three canonical characteristics of relaxing liquids are correlated through the fragility. As a further new twist, the conversion of strong liquids to fragile liquids by pressure-induced coordination number increases is demonstrated. It is then shown that, for comparable systems, it is possible to have the same conversion accomplished via a first-order transition within the liquid state during quenching. This occurs in the systems in which "polyamorphism" (polymorphism in the glassy state) is observed, and the whole phenomenology is accounted for by Poole's bond-modified van der Waals model. The sudden loss of some liquid degrees of freedom through such weak first-order transitions is then related to the polyamorphic transition between native and denatured hydrated proteins, since the latter are also glass-forming systems-water-plasticized, hydrogen bond-cross-linked chain polymers (and single molecule glass formers). The circle is closed with a final new twist by noting that a short time scale phenomenon much studied by protein physicists-namely, the onset of a sharp change in d/dT ( is the Debye-Waller factor)-is general for glass-forming liquids, including computer-simulated strong and fragile ionic liquids, and is closely correlated with the experimental glass transition temperature. The latter thus originates in strong anharmonicity in certain components of the vibrational density of states, which permits the system to access the multiple minima of its configuration space. The connection between the anharmonicity in these modes, vibrational localization, the Kauzmann temperature, and the fragility of the liquid is proposed as the key problem in glass science. The publication costs of this article were defrayed in part by page charge payment. This article must therefore be hereby marked "advertisement" in accordance with 18 U.S.C. §1734 solely to indicate this fact. mediate range order (4), has been found (5-7) to correlate with the temperature dependence of the viscosity (i.e., with the so-called "fragility" of the liquid or polymer). At the same time, the notion that a given liquid on slow cooling at constant pressure always tends toward the same conformational ground state has recently been overturned by the recognition of the existence of polymorphism in the glassy state (8-11) [called "polyamorphism" (12)]. Thus the field is in a state of flux. It is an exciting period, as Anderson has opined (13), that a theory of the nature of glass and the glass transition is the "deepest and most interesting unsolved problem in solid state theory."Many of the pro...

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Vibrational spectra in fluoride crystals and glasses at normal and high pressures by computer simulation

Cited by 63 publications

References 14 publications

Femtosecond laser induced structural changes in fluorozirconate glass

Femtosecond laser induced structural changes in fluorozirconate glass

Understanding the interface between silicon-based materials and water: Molecular-dynamics exploration of infrared spectra

The old problems of glass and the glass transition, and the many new twists.

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