Macroscopic Separation of Dense Fluid Phase and Liquid Phase of Phosphorus

Katayama, Yoshinori; Inamura, Yasuhiro; Mizutani, Takeshi; Yamakata, Masaaki; Utsumi, Wataru; Shimomura, Osamu

doi:10.1126/science.1102735

Cited by 172 publications

(85 citation statements)

References 23 publications

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“…This observation allows us to conclude that the possibility of a liquid-liquid critical point is not limited to fluids with density anomalies-a conclusion supported by recent experiments for phosphorus [68][69][70] and triphenyl phosphite [71,72].…”

Section: Discussionsupporting

confidence: 61%

The Widom line of supercooled water

Franzese¹,

Stanley²

2007

J. Phys.: Condens. Matter

165

204

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Water can be supercooled to temperatures as low as −92• C, the experimental crystal homogeneous nucleation temperature T H at 2 kbar. Within the supercooled liquid phase its response functions show an anomalous increase consistent with the presence of a liquid-liquid critical point located in a region inaccessible to experiments on bulk water. Recent experiments on the dynamics of confined water show that a possible way to understand the properties of water is to investigate the supercooled phase diagram in the vicinity of the Widom line (locus of maximum correlation length) that emanates from the hypothesized liquid-liquid critical point. Here we explore the Widom line for a Hamiltonian model of water using an analytic approach, and discuss the plausibility of the hypothesized liquid-liquid critical point, as well as its possible consequences, on the basis of the assumptions of the model. The present analysis allows us (i) to find an analytic expression for the spinodal line of the high-density liquid phase, with respect to the low-density liquid phase, showing that this line becomes flat in the P-T phase diagram in the physical limit of a large number of available orientations for the hydrogen bonds, as recently seen in simulations and experiments (Xu et al 2005 Proc. Natl Acad. Sci. 102 16558); (ii) to find an estimate of the values for the hypothesized liquid-liquid critical point coordinates that compare very well with Monte Carlo results; and (iii) to show how the Widom line can be located by studying the derivative of the probability of forming hydrogen bonds with local tetrahedral orientation which can be calculated analytically within this approach.

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Section: Discussionsupporting

confidence: 61%

The Widom line of supercooled water

Franzese¹,

Stanley²

2007

J. Phys.: Condens. Matter

165

204

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“…multiple structures of amorphous materials with the same composition separated by a first order phase transition) remains a fundamentally important and unresolved phenomenon [408]. A wealth of indirect evidence for such transitions has already been established in H2O [407], SiO2 [200,409,410], GeO2 [61,224,411], Si [198,412,413], I [414], Se [414,415], S [415,416], P [197,417], Ce [406]. However, unambiguous evidence for liquid-liquid transition has yet to be presented in the liquid state for any system.…”

Section: Non-crystalline Materialsmentioning

confidence: 99%

High-pressure studies with x-rays using diamond anvil cells

2016

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Pressure profoundly alters all states of matter. The symbiotic development of ultrahighpressure diamond anvil cells, to compress samples to sustainable multi-megabar pressures; and synchrotron x-ray techniques, to probe materials' properties in situ, has enabled the exploration of rich high-pressure (HP) science. In this article, we first introduce the essential concept of diamond anvil cell technology, together with recent developments and its integration with other extreme environments. We then provide an overview of the latest developments in HP synchrotron techniques, their applications, and current problems, followed by a discussion of HP scientific studies using x-rays in the key multidisciplinary fields. These HP studies include: HP x-ray emission spectroscopy, which provides information on the filled electronic states of HP samples; HP x-ray Raman spectroscopy, which probes the HP chemical bonding changes of light elements; HP electronic inelastic x-ray scattering spectroscopy, which accesses high energy electronic phenomena, including electronic band structure, Fermi surface, excitons, plasmons, and their dispersions; HP resonant inelastic x-ray scattering spectroscopy, which probes shallow core excitations, multiplet structures, and spin-resolved electronic structure; HP nuclear resonant x-ray spectroscopy, which provides phonon densities of state and time-resolved Mössbauer information; HP x-ray imaging, which provides information on hierarchical structures, dynamic processes, and internal strains; HP x-ray diffraction, which determines the fundamental structures and densities of single-crystal, polycrystalline, nanocrystalline, and non-crystalline materials; and HP radial x-ray diffraction, which yields deviatoric, elastic and rheological information. Integrating these tools with hydrostatic or uniaxial pressure media, laser and resistive heating, and cryogenic cooling, has enabled investigations of the structural, vibrational, electronic, and magnetic properties of materials over a wide range of pressure-temperature conditions.

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“…To this end, we introduce three quantities of physical interest: (i) the space-dependent correlation function C Q (r), (ii) the timedependent autocorrelation function C Q (t), and (iii) the tetrahedral entropy S Q . These functions can also be usefully applied to study other locally tetrahedral liquids, such as silicon (23)(24)(25), silica (26), and phosphorus (27).…”

Section: Introductionmentioning

confidence: 99%

A tetrahedral entropy for water

Kumar

Buldyrev

Stanley

2009

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

104

124

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We introduce the space-dependent correlation function C Q (r) and time-dependent autocorrelation function C Q (t) of the local tetrahedral order parameter Q ≡ Q(r, t). By using computer simulations of 512 waterlike particles interacting through the transferable interaction potential with five points (TIP5 potential), we investigate C Q (r) in a broad region of the phase diagram. We find that at low temperatures C Q (t) exhibits a two-step time-dependent decay similar to the self-intermediate scattering function and that the corresponding correlation time τ Q displays a dynamic cross-over from non-Arrhenius behavior for T > T W to Arrhenius behavior for T < T W , where T W denotes the Widom temperature where the correlation length has a maximum as T is decreased along a constant-pressure path. We define a tetrahedral entropy S Q associated with the local tetrahedral order of water molecules and find that it produces a major contribution to the specific heat maximum at the Widom line. Finally, we show that τ Q can be extracted from S Q by using an analog of the Adam-Gibbs relation.specific heat of water | orientational entropy of tetrahedral liquids | anomalies of liquid water | Widom line I t has long been appreciated that the local structure around a molecule of liquid water arising from the vertices formed by four nearest neighbors is approximately tetrahedral at ambient pressure and that the degree of tetrahedrality increases when water is cooled (1-5). An important advance occurred in the past 10 years when computer simulations allowed the quantification of the degree of tetrahedrality (6-10) by assigning to each molecule a local tetrahedral order parameter Q (11-16). At high temperatures, the probability distribution P(Q, T) is bimodal, with one peak corresponding to a high degree of tetrahedrality and the other to a less tetrahedral environment (Fig. 1). Upon decreasing temperature, the peak associated with a high degree of tetrahedrality grows, suggesting that the local structure of water becomes much more tetrahedral at lower temperatures (13,14,17). IntroductionWater has been hypothesized to belong to the class of polymorphic liquids, phase separating-at sufficiently low temperatures and high pressures-into two distinct liquid phases: a high density liquid (HDL) with smaller Q and a low density liquid (LDL) with larger Q (18). The coexistence line separating these two phases may terminate at a liquid-liquid (LL) critical point, above which (in the LL supercritical region) appears a line of correlation length maximum in the pressure-temperature plane. The locus of maximum correlation length in the one-phase region is called the Widom line T W ≡ T W (P) (19), near which different response functions, such as isobaric specific heat C P and isothermal compressibility K T , display maxima. Recent neutron-scattering experiments (20) and computer simulations (19) show that the dynamics of water gradually cross over from being non-Arrhenius for T > T W to Arrhenius for T < T W .Although dynamic heterogeneities h...

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Macroscopic Separation of Dense Fluid Phase and Liquid Phase of Phosphorus

Cited by 172 publications

References 23 publications

The Widom line of supercooled water

The Widom line of supercooled water

High-pressure studies with x-rays using diamond anvil cells

A tetrahedral entropy for water

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