Structures of High-Density and Low-Density Water

Soper, A. K.; Ricci, Maria Antonietta

doi:10.1103/physrevlett.84.2881

Cited by 632 publications

(659 citation statements)

References 28 publications

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“…However, regarding the deposited energy as equivalent to a local heating of the liquid it is most likely the librational mode that will mediate a structural transformation, where the water molecule will rotate out to avoid directional H-bonds. When comparing HDA ice to LDA ice, it is mostly bending of H-bonds that occurs 69 and we anticipate similar changes in a conversion of tetrahedrally H-bonded structures to local structures with distorted H-bonds at low temperatures. The vibrational period of the librational mode is of the order of 50 fs and a fractional period of motion could occur on a few femtoseconds to tens of femtoseconds timescale.…”

Section: Discussionmentioning

confidence: 94%

X-ray emission spectroscopy of bulk liquid water in “no-man’s land”

Sellberg

McQueen

Laksmono

et al. 2015

The Journal of Chemical Physics

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The structure of bulk liquid water was recently probed by x-ray scattering below the temperature limit of homogeneous nucleation (T H ) of ∼232 K [J. A. Sellberg et al., Nature 510, 381-384 (2014)]. Here, we utilize a similar approach to study the structure of bulk liquid water below T H using oxygen K-edge x-ray emission spectroscopy (XES). Based on previous XES experiments [T. Tokushima et al., Chem. Phys. Lett. 460, 387-400 (2008)] at higher temperatures, we expected the ratio of the 1b 1 ′ and 1b 1 ′′ peaks associated with the lone-pair orbital in water to change strongly upon deep supercooling as the coordination of the hydrogen (H-) bonds becomes tetrahedral. In contrast, we observed only minor changes in the lone-pair spectral region, challenging an interpretation in terms of two interconverting species. A number of alternative hypotheses to explain the results are put forward and discussed. Although the spectra can be explained by various contributions from these hypotheses, we here emphasize the interpretation that the line shape of each component changes dramatically when approaching lower temperatures, where, in particular, the peak assigned to the proposed disordered component would become more symmetrical as vibrational interference becomes more important. C 2015 AIP Publishing LLC. [http://dx

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Section: Discussionmentioning

confidence: 94%

X-ray emission spectroscopy of bulk liquid water in “no-man’s land”

Sellberg

McQueen

Laksmono

et al. 2015

The Journal of Chemical Physics

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“…Experiments show that formation of the H bonds leads to an open-locally tetrahedral-structure that induces an increase of volume per molecule (2,26). This effect is incorporated in the model by considering the total volume to be given as…”

Section: Cooperative Cell Model Of Watermentioning

confidence: 99%

Effect of hydrogen bond cooperativity on the behavior of water

Stokely

Mazza

Stanley

et al. 2010

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

263

250

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Four scenarios have been proposed for the low-temperature phase behavior of liquid water, each predicting different thermodynamics. The physical mechanism that leads to each is debated. Moreover, it is still unclear which of the scenarios best describes water, because there is no definitive experimental test. Here we address both open issues within the framework of a microscopic cell model by performing a study combining mean-field calculations and Monte Carlo simulations. We show that a common physical mechanism underlies each of the four scenarios, and that two key physical quantities determine which of the four scenarios describes water: (i) the strength of the directional component of the hydrogen bond and (ii) the strength of the cooperative component of the hydrogen bond. The four scenarios may be mapped in the space of these two quantities. We argue that our conclusions are model independent. Using estimates from experimental data for H-bond properties the model predicts that the low-temperature phase diagram of water exhibits a liquid-liquid critical point at positive pressure.anomalous liquids | liquid-liquid transition | liquid water | mean field | Monte Carlo simulations W ater's phase diagram is rich and complex: more than sixteen crystalline phases (1), and two or more glasses (2-4) have been reported. The liquid state also displays interesting behavior, such as the density maximum for 1 atm at 4°C. The volume fluctuations hðδV Þ 2 i, entropy fluctuations hðδSÞ 2 i, and cross fluctuations between volume and entropy hδV δSi, proportional to the magnitude of isothermal compressibility K T , isobaric specific heat C P , and isobaric thermal expansivity α P , respectively, show anomalous increases in magnitude upon cooling (5). Further, these quantities display an apparent divergence for 1 atm at −45°C (2), hinting at interesting phase behavior in the supercooled region.Microscopically, liquid water's anomalous behavior is understood as resulting from the tendency of neighboring molecules to form hydrogen (H) bonds upon cooling with a decrease of local potential energy, decrease of local entropy, and increase of local volume due to the formation of local open structures of bonded molecules. Different models include these H-bond features, but depending on the assumptions and approximations of each model, different conclusions are obtained for the low-T phase behavior. The relevant region of the bulk-liquid state cannot be probed experimentally, and none of the theories tested because crystallization of bulk water is unavoidable below the homogeneous nucleation temperature T H (−38°C at 1 atm). Four Scenarios for Supercooled WaterDue to the difficulty of obtaining experimental evidence, theoretical and numerical analyses are useful. Four separate scenarios for the pressure-temperature (P-T) phase diagram have been proposed: (I) The stability limit (SL) scenario (6) hypothesizes that the superheated liquid-gas spinodal at negative pressure reenters the positive P region below T H ðPÞ. In this view, the liq...

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“…The first population, with a high value of ζ, is characterized by an open tetrahedral structure, while the second population, with a small value of ζ, is characterized by a collapsed second nearest-neighbor shell, with substantial shell interpenetration. Supercooled water structures can thus be divided in two different states that differ for the structure of their second nearest-neighbor shell [215,216]. Locally favored states are represented by a Gaussian population centered around a finite positive value of ζ, while the disordered state by a Gaussian population centered around a null value of ζ, with abundant number of states with shell interpenetration (ζ < 0).…”

Section: Local Structural Ordering and Thermodynamic Anomalies Of Watermentioning

confidence: 99%

Crystal nucleation as the ordering of multiple order parameters

Russo

Tanaka

2016

The Journal of Chemical Physics

107

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Nucleation is an activated process in which the system has to overcome a free energy barrier in order for a first-order phase transition between the metastable and the stable phases to take place. In the liquid-to-solid transition the process occurs between phases of different symmetry, and it is thus inherently a multi-dimensional process, in which all symmetries are broken at the transition. In this Focus Article, we consider some recent studies which highlight the multi-dimensional nature of the nucleation process. Even for a single-component system, the formation of solid crystals from the metastable melt involves fluctuations of two (or more) order parameters, often associated with the decoupling of positional and orientational symmetry breaking. In other words, we need at least two order parameters to describe the free-energy of a system including its liquid and crystalline states. This decoupling occurs naturally for asymmetric particles or directional interactions, focusing here on the case of water, but we will show that it also affects spherically symmetric interacting particles, such as the hard-sphere system. We will show how the treatment of nucleation as a multi-dimensional process has shed new light on the process of polymorph selection, on the effect of external fields on the nucleation process, and on glass-forming ability.

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Structures of High-Density and Low-Density Water

Cited by 632 publications

References 28 publications

X-ray emission spectroscopy of bulk liquid water in “no-man’s land”

X-ray emission spectroscopy of bulk liquid water in “no-man’s land”

Effect of hydrogen bond cooperativity on the behavior of water

Crystal nucleation as the ordering of multiple order parameters

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