A second distinct structural “state” of high-density amorphous ice at 77 K and 1 bar

Loerting, Thomas; Salzmann, Christoph G.; Kohl, Ingrid; Mayer, Erwin; Hallbrucker, Andreas

doi:10.1039/b108676f

Cited by 314 publications

(400 citation statements)

References 17 publications

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“…Recently, it has been found that upon annealing or heating isobarically samples of HDA at high-P , the glass becomes denser [49]; the resulting glass is called very-high-density glass (VHDA) or relaxed HDA (RHDA) [26,29,30]. VHDA/RHDA can also be obtained in computer simulations using the SPC/E [30] and the TIP4P models [29].…”

Section: B Annealed Amorphous Icementioning

confidence: 99%

Structural order in glassy water

et al. 2005

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We investigate structural order in glassy water by performing classical molecular dynamics simulations using the extended simple point charge (SPC/E) model of water. We perform isochoric cooling simulations across the glass transition temperature at different cooling rates and densities. We quantify structural order by orientational and translational order metrics. Upon cooling the liquid into the glassy state, both the orientational order parameter Q and translational order parameter τ increase. At T = 0 K, the glasses fall on a line in the Q-τ plane or order map. The position of this line depends only on density and coincides with the location in the order map of the inherent structures (IS) sampled upon cooling. We evaluate the energy of the IS, e IS (T ), and find that both order parameters for the IS are proportional to e IS . We also study the structural order during the transformation of low-density amorphous ice (LDA) to high-density amorphous ice (HDA) upon isothermal compression and are able to identify distinct regions in the 1 order map corresponding to these glasses. Comparison of the order parameters for LDA and HDA with those obtained upon isochoric cooling indicates major structural differences between glasses obtained by cooling and glasses obtained by compression. These structural differences are only weakly reflected in the pair correlation function. We also characterize the evolution of structural order upon isobaric annealing, leading at high pressure to very-high density amorphous ice (VHDA).

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Section: B Annealed Amorphous Icementioning

confidence: 99%

Structural order in glassy water

et al. 2005

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“…We note that in Ref. [6] the samples annealed at 11 and 19 kbar reached the same density upon decompression. The clear similarity of the RDF of RP decompressed from 19.5 kbar to that of VHDA recovered at p = 0 in experiment [8] manifested in the distinct peak at r = 3.37Å, very close to the first shell peak, allows us to identify this form as VHDA.…”

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confidence: 99%

“…The radial distribution function (RDF) of HDA' at p = 0 is shown in Fig.2; it has a broad second peak between 3.3 and 4.6Å, very similar to that of HDA at p = 0 [7]. Inspired by the experiments [6] that led to the discovery of the VHDA we decided to anneal the HDA' phase at each intermediate pressure between 22.5 kbar and zero [20] in order to search for possible new structures. Annealing was performed by heating up to T = 170 K and subsequent cooling down to 80 K; the temperature was always changed in steps of 10 K. The phase obtained in this way will be called relaxed phase (RP).…”

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confidence: 99%

“…Recently several new experimental results [6,7,8,9,10,11] raised new questions about the polyamorphism of ice.…”

mentioning

confidence: 99%

“…A new amorphous form of ice has been reported [6], prepared by heating HDA under pressure of 11 kbar to T ∼ 170 K and cooling it back to T = 80 K; when recovered at ambient pressure it has a density of ∼ 1.25 g/cm 3 . It has been called very high-density amorphous ice (VHDA) and characterized experimentally using neutron diffraction [8].…”

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Polyamorphism of Ice at Low Temperatures from Constant-Pressure Simulations

2004

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We report results of MD simulations of amorphous ice in the pressure range 0 -22.5 kbar. The high-density amorphous ice (HDA) prepared by compression of I h ice at T = 80 K is annealed to T = 170 K at intermediate pressures in order to generate relaxed states. We confirm the existence of recently observed phenomena, the very high-density amorphous ice and a continuum of HDA forms. We suggest that both phenomena have their origin in the evolution of the network topology of the annealed HDA phase with decreasing volume, resulting at low temperatures in the metastability of a range of densities.

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Water, Properties of

Geiger

Paschek

2008

Wiley Encyclopedia of Chemical Biology

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Water is well known for its unusual properties, which are the so‐called “anomalies” of the pure liquid, as well as for its special behavior as solvent, such as the hydrophobic hydration effects. During the past few years, a wealth of new insights into the origin of these features has been obtained by various experimental approaches and from computer simulation studies. In this review, we discuss points of special interest in the current water research. These points comprise the unusual properties of supercooled water, including the occurrence of liquid–liquid phase transitions, the related structural changes, and the onset of the unusual temperature dependence of the dynamics of the water molecules. The problem of the hydrogen‐bond network in the pure liquid, in aqueous mixtures and in solutions, can be approached by percolation theory. The properties of ionic and hydrophobic solvation are discussed in detail.

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A second distinct structural “state” of high-density amorphous ice at 77 K and 1 bar

Cited by 314 publications

References 17 publications

Structural order in glassy water

Structural order in glassy water

Polyamorphism of Ice at Low Temperatures from Constant-Pressure Simulations

Water, Properties of

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