Structures and phase transitions of amorphous ices

Okabe, Ichiro; Tanaka, Hideki; Nakanishi, Koichiro

doi:10.1103/physreve.53.2638

Cited by 47 publications

(41 citation statements)

References 35 publications

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“…It is interesting also to study the effects that confinement may have on the phase transition properties of supercooled water [96], in order to clarify the possible presence of a LL phase transition in the water Recent work on the phase behavior of confined water suggests a sensitive dependence on the interaction with the surfaces [104], as a LL phase transition appears to be consistent with simulations of water confined between two parallel flat hydrophobic walls [94]. Works are in progress to extend this work to hydrophilic pores, such as those in Vycor glasses or biological situations, and to hydrophobic hydrogels, systems of current experimental interest [106,107,108,109,110,111,112,113,114,115,94,116,117,118,119,120,121].…”

Section: Selected Results From Simulationssupporting

confidence: 60%

Liquid Polyamorphism: Some Unsolved Puzzles of Water in Bulk, Nanoconfined, and Biological Environments

Stanley¹,

Kumar²,

Franzese³

et al. 2008

AIP Conference Proceedings

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Abstract. We investigate the relation between changes in dynamic and thermodynamic anomalies arising from the presence of the liquid-liquid critical point in (i) Two models of water, TIP5P and ST2, which display a first order liquid-liquid phase transition at low temperatures; (ii) the Jagla model, a spherically symmetric two-scale potential known to possess a liquid-liquid critical point, in which the competition between two liquid structures is generated by repulsive and attractive ramp interactions; and (iii) A Hamiltonian model of water where the idea of two length/energy scales is built in; this model also displays a first order liquid-liquid phase transition at low temperatures besides the first order liquid-gas phase transition at high temperatures. We find a correlation between the dynamic fragility crossover and the locus of specific heat maxima Cp'^'^ ("Widom line") emanating from the critical point. Our findings are consistent with a possible relation between the previously hypothesized liquid-liquid phase transition and the transition in the dynamics recently observed in neutron scattering experiments on confined water. More generally, we argue that this connection between Cp'^'^ and the dynamic crossover is not limited to the case of water, a hydrogen bonded network liquid, but is a more general feature of crossing the Widom line, an extension of the first-order coexistence line in the supercritical region. We present evidence from experiments and computer simulations supporting the hypothesis that water displays polyamorphism, i.e., water separates into two distinct liquid phases. This concept of a new liquid-liquid phase transition is finding application to other liquids as well as water, such as silicon and silica. We also discuss related puzzles, such as the mysterious behavior of confined water and the "skin" of hydration water near a biomolecule. Specifically, using molecular dynamics simulations, we also investigate the relation between the dynamic transitions of biomolecules (lysozyme and DNA) and the dynamic and thermodynamic properties of hydration water. We find that the dynamic transition of the macromolecules, sometimes called a "protein glass transition", occurs at the temperature of dynamic crossover in the diffusivity of hydration water, and also coincides with the maxima of the isobaric specific heat Cp and the temperature derivative of the orientational order parameter. We relate these findings to the hypothesis of a liquid-liquid critical point in water. Our simulations are consistent with the possibility that the protein glass transition results from a change in the behavior of hydration water, specifically from crossing the Widom line.

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Section: Selected Results From Simulationssupporting

confidence: 60%

Liquid Polyamorphism: Some Unsolved Puzzles of Water in Bulk, Nanoconfined, and Biological Environments

Stanley¹,

Kumar²,

Franzese³

et al. 2008

AIP Conference Proceedings

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“…67 (P s = 1.19 ± 0.05 GPa), and to the amorphization pressure obtained in Ref. 22 from classical molecular dynamics simulations. From 1 to 2 GPa the volume decreases by 27%, and at higher pressures it continues decreasing to reach a value of 10.8 cm 3 /mol at P = 8 GPa, to be compared with v = 19.36 cm 3 /mol found for ice Ih at atmospheric pressure.…”

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confidence: 61%

High-density amorphous ice: A path-integral simulation

Herrero

Ramı́rez

2012

The Journal of Chemical Physics

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Structural and thermodynamic properties of high-density amorphous (HDA) ice have been studied by path-integral molecular dynamics simulations in the isothermal-isobaric ensemble. Interatomic interactions were modeled by using the effective q-TIP4P/F potential for flexible water. Quantum nuclear motion is found to affect several observable properties of the amorphous solid. At low temperature (T = 50 K) the molar volume of HDA ice is found to increase by 6%, and the intramolecular O-H distance rises by 1.4% due to quantum motion. Peaks in the radial distribution function of HDA ice are broadened respect to their classical expectancy. The bulk modulus, B, is found to rise linearly with the pressure, with a slope ∂B/∂P = 7.1. Our results are compared with those derived earlier from classical and path-integral simulations of HDA ice. We discuss similarities and discrepancies with those earlier simulations.

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“…At the same time they can provide detailed structural information which might not be easily extracted from the experimental data. The basic phenomenology of amorphous ices has been reproduced in earlier works 8,23,24 . New simulations have also been performed recently 25 Here we present the results of extensive constantpressure MD simulations of amorphous ice at temperatures 80 -170 K and pressures up to 22.5 kbar.…”

Section: Introductionmentioning

confidence: 99%

Evolution of the structure of amorphous ice: From low-density amorphous through high-density amorphous to very high-density amorphous ice

Martoňák

Donadio

Parrinello

2005

The Journal of Chemical Physics

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We report results of molecular dynamics simulations of amorphous ice for pressures up to 22.5 kbar. The high-density amorphous ice (HDA) as prepared by pressure-induced amorphization of I h ice at T = 80 K is annealed to T = 170 K at various pressures to allow for relaxation. Upon increase of pressure, relaxed amorphous ice undergoes a pronounced change of structure, ranging from the low-density amorphous ice (LDA) at p = 0, through a continuum of HDA states to the limiting very high-density amorphous ice (VHDA) regime above 10 kbar. The main part of the overall structural change takes place within the HDA megabasin, which includes a variety of structures with quite different local and medium-range order as well as network topology and spans a broad range of densities. The VHDA represents the limit to densification by adapting the hydrogen-bonded network topology, without creating interpenetrating networks. The connection between structure and metastability of various forms upon decompression and heating is studied and discussed. We also discuss the analogy with amorphous and crystalline silica. Finally, some conclusions concerning the relation between amorphous ice and supercooled water are drawn.

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Structures and phase transitions of amorphous ices

Cited by 47 publications

References 35 publications

Liquid Polyamorphism: Some Unsolved Puzzles of Water in Bulk, Nanoconfined, and Biological Environments

Liquid Polyamorphism: Some Unsolved Puzzles of Water in Bulk, Nanoconfined, and Biological Environments

High-density amorphous ice: A path-integral simulation

Evolution of the structure of amorphous ice: From low-density amorphous through high-density amorphous to very high-density amorphous ice

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