Relations between thermodynamics, structures, and dynamics for modified water models in their supercooled regimes

Horstmann, Robin; Vogel, Michael

doi:10.1063/5.0037080

Cited by 7 publications

(5 citation statements)

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“…3) 62 . This observation lends credence to the structurally based interpretation of water's dynamic anomalies 59,60 . We also calculated other fluid properties at T g , such as density and thermal expansion coefficient, which showed similarly anomalous behavior for pressures below P c ; we discuss these trends briefly in Supplementary Fig.…”

Section: Resultssupporting

confidence: 71%

“…The anomalous minimum in T g vs. P for water-like models has been shown to be associated with the locus of maximum diffusivity in the fluid as a function of pressure (D max (P)) 58 . Furthermore, supercooled water's anomalous dynamics (of which D max (P) is a notable aspect) can be rationalized in terms of water's tendency to form locally favored structures at low temperatures and pressures and a possible crossover from LDL-like to HDL-like liquids 59,60 . In the present work, pressures at which T g vs. P exhibited a negative slope corresponded to LDA-like 61 structures as characterized by the S (k) and the oxygen-oxygen radial distribution function ((S(k) and g(r), see Supplementary Figs.…”

Section: Resultsmentioning

confidence: 99%

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Manifestations of metastable criticality in the long-range structure of model water glasses

et al. 2021

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Much attention has been devoted to water’s metastable phase behavior, including polyamorphism (multiple amorphous solid phases), and the hypothesized liquid-liquid transition and associated critical point. However, the possible relationship between these phenomena remains incompletely understood. Using molecular dynamics simulations of the realistic TIP4P/2005 model, we found a striking signature of the liquid-liquid critical point in the structure of water glasses, manifested as a pronounced increase in long-range density fluctuations at pressures proximate to the critical pressure. By contrast, these signatures were absent in glasses of two model systems that lack a critical point. We also characterized the departure from equilibrium upon vitrification via the non-equilibrium index; water-like systems exhibited a strong pressure dependence in this metric, whereas simple liquids did not. These results reflect a surprising relationship between the metastable equilibrium phenomenon of liquid-liquid criticality and the non-equilibrium structure of glassy water, with implications for our understanding of water phase behavior and glass physics. Our calculations suggest a possible experimental route to probing the existence of the liquid-liquid transition in water and other fluids.

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Section: Resultssupporting

confidence: 71%

Section: Resultsmentioning

confidence: 99%

Manifestations of metastable criticality in the long-range structure of model water glasses

et al. 2021

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“…This is important since (i) the LLCP scenario has been tested only in classical MD simulations and, mostly, rigid water models, and (ii) the location of the LLCP is extremely sensitive to small variations in the water model considered (e.g., small changes in the partial charges of the H and O atoms can easily shift the location of the LLCP to ( P , T ) conditions that are physically inaccessible to the liquid state; see, e.g., Refs. 76 , 77 ). Overall, including NQE shifts the location of the LLCP, LLPT line, and maxima/minima lines towards lower temperatures (see also Ref.…”

Section: Resultsmentioning

confidence: 99%

Evidence of a liquid–liquid phase transition in H$$_2$$O and D$$_2$$O from path-integral molecular dynamics simulations

Eltareb

López

Giovambattista

2022

Sci Rep

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We perform path-integral molecular dynamics (PIMD), ring-polymer MD (RPMD), and classical MD simulations of H$$_2$$ 2 O and D$$_2$$ 2 O using the q-TIP4P/F water model over a wide range of temperatures and pressures. The density $$\rho (T)$$ ρ ( T ) , isothermal compressibility $$\kappa _T(T)$$ κ T ( T ) , and self-diffusion coefficients D(T) of H$$_2$$ 2 O and D$$_2$$ 2 O are in excellent agreement with available experimental data; the isobaric heat capacity $$C_P(T)$$ C P ( T ) obtained from PIMD and MD simulations agree qualitatively well with the experiments. Some of these thermodynamic properties exhibit anomalous maxima upon isobaric cooling, consistent with recent experiments and with the possibility that H$$_2$$ 2 O and D$$_2$$ 2 O exhibit a liquid-liquid critical point (LLCP) at low temperatures and positive pressures. The data from PIMD/MD for H$$_2$$ 2 O and D$$_2$$ 2 O can be fitted remarkably well using the Two-State-Equation-of-State (TSEOS). Using the TSEOS, we estimate that the LLCP for q-TIP4P/F H$$_2$$ 2 O, from PIMD simulations, is located at $$P_c = 167 \pm 9$$ P c = 167 ± 9 MPa, $$T_c = 159 \pm 6$$ T c = 159 ± 6 K, and $$\rho _c = 1.02 \pm 0.01$$ ρ c = 1.02 ± 0.01 g/cm$$^3$$ 3 . Isotope substitution effects are important; the LLCP location in q-TIP4P/F D$$_2$$ 2 O is estimated to be $$P_c = 176 \pm 4$$ P c = 176 ± 4 MPa, $$T_c = 177 \pm 2$$ T c = 177 ± 2 K, and $$\rho _c = 1.13 \pm 0.01$$ ρ c = 1.13 ± 0.01 g/cm$$^3$$ 3 . Interestingly, for the water model studied, differences in the LLCP location from PIMD and MD simulations suggest that nuclear quantum effects (i.e., atoms delocalization) play an important role in the thermodynamics of water around the LLCP (from the MD simulations of q-TIP4P/F water, $$P_c = 203 \pm 4$$ P c = 203 ± 4 MPa, $$T_c = 175 \pm 2$$ T c = 175 ± 2 K, and $$\rho _c = 1.03 \pm 0.01$$ ρ c = 1.03 ± 0.01 g/cm$$^3$$ 3 ). Overall, our results strongly support the LLPT scenario to explain water anomalous behavior, independently of the fundamental differences between classical MD and PIMD techniques. The reported values of $$T_c$$ T c for D$$_2$$ 2 O and, particularly, H$$_2$$ 2 O suggest that improved water models are needed for the study of supercooled water.

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“…An equation of state based on interconversion of alternative structures incorporating a LLT was successfully used to describe the phase behavior and thermodynamic anomalies in two simulated atomistic models of water, ST2 [12] and TIP4P/2005 [13,14] or its charge-scaled versions [15]. A similar equation of state was also used to correlate the experimental thermodynamic properties of supercooled water [16,17] and hydrogen [18].…”

Section: Introductionmentioning

confidence: 99%

Minimal microscopic model for liquid polyamorphism and water-like anomalies

Caupin,

Anisimov

2021

Preprint

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Liquid polyamorphism is the intriguing possibility for a single component substance to exist in multiple liquid phases. We propose a minimal model for this phenomenon. Starting with a classical binary lattice model with critical azeotropy and liquid-liquid demixing, we allow interconversion of the two species, turning the system into a single-component fluid with two states differing in energy and entropy. Changing one interaction parameter allows to continuously switch from a liquidliquid transition, terminated by a critical point, to a singularity-free scenario, exhibiting water-like anomalies but without polyamorphism. This resolves a controversy about how a liquid-liquid critical point can be found or not in simulations. The model provides a unified theoretical framework to describe supercooled water and a variety of polyamorphic liquids with water-like anomalies.

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Relations between thermodynamics, structures, and dynamics for modified water models in their supercooled regimes

Cited by 7 publications

References 93 publications

Manifestations of metastable criticality in the long-range structure of model water glasses

Manifestations of metastable criticality in the long-range structure of model water glasses

Evidence of a liquid–liquid phase transition in H$$_2$$O and D$$_2$$O from path-integral molecular dynamics simulations

Minimal microscopic model for liquid polyamorphism and water-like anomalies

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