Topic
Polyamorphism
About: Polyamorphism is a research topic. Over the lifetime, 588 publications have been published within this topic receiving 29122 citations.
Papers published on a yearly basis
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Papers
TL;DR: The onset of a sharp change in ddT( is the Debye-Waller factor and T is temperature) in proteins, which is controversially indentified with the glass transition in liquids, is shown to be general for glass formers and observable in computer simulations of strong and fragile ionic liquids, where it proves to be close to the experimental glass transition temperature.
Abstract: Glasses can be formed by many routes. In some cases, distinct polyamorphic forms are found. The normal mode of glass formation is cooling of a viscous liquid. Liquid behavior during cooling is classified between "strong" and "fragile," and the three canonical characteristics of relaxing liquids are correlated through the fragility. Strong liquids become fragile liquids on compression. In some cases, such conversions occur during cooling by a weak first-order transition. This behavior can be related to the polymorphism in a glass state through a recent simple modification of the van der Waals model for tetrahedrally bonded liquids. The sudden loss of some liquid degrees of freedom through such first-order transitions is suggestive of the polyamorphic transition between native and denatured hydrated proteins, which can be interpreted as single-chain glass-forming polymers plasticized by water and cross-linked by hydrogen bonds. The onset of a sharp change in d dT( is the Debye-Waller factor and T is temperature) in proteins, which is controversially indentified with the glass transition in liquids, is shown to be general for glass formers and observable in computer simulations of strong and fragile ionic liquids, where it proves to be close to the experimental glass transition temperature. The latter may originate in strong anharmonicity in modes ("bosons"), which permits the system to access multiple minima of its configuration space. These modes, the Kauzmann temperature T(K), and the fragility of the liquid, may thus be connected.
4,772 citations
TL;DR: In this article, the authors present a comprehensive series of molecular dynamics simulations which suggest that the supercooling anomalies are caused by a newly identified critical point above which the two metastable amorphous phases of ice (previously shown to be separated by a line of first-order transitions) become indistinguishable.
Abstract: THE metastable extension of the phase diagram of liquid water exhibits rich features that manifest themselves in the equilibrium properties of water. For example, the density maximum at 4 °C and the minimum in the isothermal compressibility at 46 °C are thought to reflect the presence of singularities in the behaviour of thermodynamic quantities occurring in the supercooled region1 2. The 'stability–limit conjecture'3–5 suggests that these thermodynamic anomalies arise from a single limit of mechanical stability (spinodal line), originating at the liquid–gas critical point, which determines the limit of both superheating at high temperatures and supercooling at low temperatures. Here we present a comprehensive series of molecular dynamics simulations which suggest that, instead, the supercooling anomalies are caused by a newly identified critical point, above which the two metastable amorphous phases of ice (previously shown to be separated by a line of first-order transitions6,7) become indistinguishable. The two amorphous ice phases are thus incorporated into our understanding of the liquid state, providing a more complete picture of the metastable and stable behaviour of water.
1,917 citations
TL;DR: This article showed that water can exist in two distinct "glassy" forms, low and high density amorphous ice, which may provide the key to understanding some of the puzzling characteristics of cold and supercooled water.
Abstract: That water can exist in two distinct ‘glassy’ forms — low- and high-density amorphous ice — may provide the key to understanding some of the puzzling characteristics of cold and supercooled water, of which the glassy solids are more-viscous counterparts. Recent experimental and theoretical studies of both liquid and glassy water are now starting to offer the prospect of a coherent picture of the unusual properties of this ubiquitous substance.
1,899 citations
TL;DR: Amorphous solids are made mainly by cooling the liquid below the glass transition without crystallizing it, a method used since before recorded history1, and by depositing the vapour onto a cold plate2, as well as by several other methods as discussed by the authors.
Abstract: Amorphous solids are made mainly by cooling the liquid below the glass transition without crystallizing it, a method used since before recorded history1, and by depositing the vapour onto a cold plate2, as well as by several other methods3,4. We report here a new way—by ‘melting’ a solid by pressure below the glass transition of the liquid—and apply it to making a new kind of amorphous ice. Thus, ice I has been transformed to an amorphous phase, as determined by X-ray diffraction, by pressurizing it at 77 K to its extrapolated melting point of 10 kbar. At the melting point, the fluid is well below its glass transition. On heating at a rate of ∼2.6 K min−1 at zero pressure it transforms at ∼117 K to a second amorphous phase with a heat evolution of 42±∼8 J g−1 and at ∼152 K further transforms to ice I with a heat evolution of 92±∼15 J g−1. In one sample, ice Ic was formed and in another, existing crystals of ice Ih grew from the amorphous phase. Heating below the 117 K transition causes irreversible changes in the diffraction pattern, and a continuous range of amorphous phases can be made. Similar transformations will probably occur in all solids whose melting point decreases with increasing pressure if they can be cooled sufficiently for a transformation to a crystalline solid to be too slow.
1,271 citations
TL;DR: In this article, it was shown that low-density amorphous ice (density 0.94 g cm−3) compressed at 77 K transforms to high-density Amorphous Ice (1.19 g cm −3 at zero pressure) at a sharp transition at 6±0.5 kbar.
Abstract: We recently reported1 a transition from ice Ih to a high-density amorphous phase at 10 kbar, 77 K. Here we report that low-density amorphous ice (density 0.94 g cm−3) compressed at 77 K transforms to high-density amorphous ice (1.19 g cm−3 at zero pressure) at a sharp transition at 6±0.5 kbar. The transition is at least as sharp as the previously reported1 transition and strongly resembles a first-order transition in its sharpness and large volume change. It appears to be the first example of an apparently first-order transition between amorphous solids and has implications not only for our understanding of the behaviour of condensed matter, but also for theories of planetary interiors.
1,062 citations
Related Topics (5)
Performance Metrics
| Year | Papers |
|---|---|
| 2025 | 5 |
| 2024 | 11 |
| 2023 | 19 |
| 2022 | 33 |
| 2021 | 21 |
| 2020 | 13 |