Dynamic crossover and liquid-liquid critical point in the TIP5P model of water

Kumar, Pradeep; Buldyrev, Sergey V.; Stanley, H. Eugene

doi:10.1007/978-1-4020-5872-1_3

Cited by 7 publications

(8 citation statements)

References 32 publications

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“…In this work we concentrated on reviewing the evidence for changes in dynamic transport properties, such as diffusion constant and relaxation time. Additional examples include: (1) a breakdown of the Stokes-Einstein relation for ToT W ðPÞ [74][75][76][77][78][79], (2) systematic changes in the static structure factor SðqÞ and the corresponding pair correlation function gðrÞ revealing that for ToT W ðPÞ the system more resembles the structure of LDL than HDL, (3) appearance for ToT W ðPÞ of a shoulder in the dynamic structure factor Sðq; oÞ at a frequency o % 60 cm À1 % 2 THz [51], (4) rapid increase in hydrogen bonding degree for ToT W ðPÞ [80,81], (5) a minimum in the density at low temperature [82], and (6) a scaled equation of state near the critical point [83]. It is important to know how general a given phenomenon is, such as crossing the Widom line which by definition is present whenever there is a critical point.…”

Section: Discussionmentioning

confidence: 99%

The puzzling unsolved mysteries of liquid water: Some recent progress

Stanley

Kumar

et al. 2007

Physica A: Statistical Mechanics and its Applications

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Water is perhaps the most ubiquitous, and the most essential, of any molecule on earth. Indeed, it defies the imagination of even the most creative science fiction writer to picture what life would be like without water. Despite decades of research, however, water's puzzling properties are not understood and 63 anomalies that distinguish water from other liquids remain unsolved. We introduce some of these unsolved mysteries, and demonstrate recent progress in solving them. We present evidence from experiments and computer simulations supporting the hypothesis that water displays a special transition point (which is not unlike the ''tipping point'' immortalized by Malcolm Gladwell). The general idea is that when the liquid is near this ''tipping point,'' it suddenly separates into two distinct liquid phases. This concept of a new critical point 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 water near a protein. r

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Section: Discussionmentioning

confidence: 99%

The puzzling unsolved mysteries of liquid water: Some recent progress

Stanley

Kumar

et al. 2007

Physica A: Statistical Mechanics and its Applications

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“…In our investigation of the thermal diffusivity of water, we perform computer simulations using the TIP5P model over a wide range of temperatures and atmospheric pressure. − The TIP5P model is able to reproduce the qualitative behavior of liquid water over a broad region of the phase diagram. The details of the interactions and simulations are discussed in refs and .…”

Section: Simulation Methodsmentioning

confidence: 99%

Thermal Conductivity Minimum: A New Water Anomaly

Kumar

Stanley

2011

J. Phys. Chem. B

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We investigate the thermal conductivity of liquid water using computer simulations of the TIP5P model of water. Our simulations show that, in addition to the maximum at high temperatures at constant pressure that it exhibits in experiments, the thermal conductivity also displays a minimum at low temperatures. We find that the temperature of minimum thermal conductivity in supercooled liquid water coincides with the temperature of maximum specific heat. We discuss our results in the context of structural changes in liquid water at low temperatures.

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“…Additional examples include: (1) a breakdown of the Stokes-Einstein relation for P < Pw{P) [192, 193? , 195, 196, 197], (2) systematic changes in the static structure factor S{q) and the corresponding pair correlation function g(r) reveahng that for P < Pw{P) the system more resembles the structure of LDL than HDL, (3) appearance for P < Pw{P) of a shoulder in the dynamic structure factor S{q, (o) at a frequency co « 60 cm^' « 2 THz [198,199], (4) rapid increase in hydrogen bonding degree for P < Pw{P) [200,201], (5) a minimum in the density at low temperature [202], and (6) a scaled equation of state near the critical point [203]. It is important to know how general a given phenomenon is, such as crossing the Widom line which by definition is present whenever there is a critical point.…”

Section: Discussionmentioning

confidence: 99%

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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Dynamic crossover and liquid-liquid critical point in the TIP5P model of water

Cited by 7 publications

References 32 publications

The puzzling unsolved mysteries of liquid water: Some recent progress

The puzzling unsolved mysteries of liquid water: Some recent progress

Thermal Conductivity Minimum: A New Water Anomaly

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

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