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Muthachikavil AV, Sun G, Peng B, Tanaka H, Kontogeorgis GM, Liang X. Unraveling thermodynamic anomalies of water: A molecular simulation approach to probe the two-state theory with atomistic and coarse-grained water models. J Chem Phys 2024; 160:154505. [PMID: 38624123 DOI: 10.1063/5.0194036] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/25/2023] [Accepted: 03/19/2024] [Indexed: 04/17/2024] Open
Abstract
Thermodynamic and dynamic anomalies of water play a crucial role in supporting life on our planet. The two-state theory attributes these anomalies to a dynamic equilibrium between locally favored tetrahedral structures (LFTSs) and disordered normal liquid structures. This theory provides a straightforward, phenomenological explanation for water's unique thermodynamic and dynamic characteristics. To validate this two-state feature, it is critical to unequivocally identify these structural motifs in a dynamically fluctuating disordered liquid. In this study, we employ a recently introduced structural parameter (θavg) that characterizes the local angular order within the first coordination shell to identify these LFTSs through molecular dynamics simulations. We employ both realistic water models with a liquid-liquid critical point (LLCP) and a coarse-grained water model without an LLCP to study water's anomalies in low-pressure regions below 2 kbar. The two-state theory consistently describes water's thermodynamic anomalies in these models, both with and without an LLCP. This suggests that the anomalies predominantly result from the two-state features rather than criticality, particularly within experimentally accessible temperature-pressure regions.
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Affiliation(s)
- Aswin V Muthachikavil
- Department of Chemical and Biochemical Engineering, Center for Energy Resources Engineering, Technical University of Denmark, Building 229, Lyngby DK-2800, Denmark
| | - Gang Sun
- Department of Physics, Center for Advanced Quantum Studies, Beijing Normal University, Beijing 100875, China
| | - Baoliang Peng
- Research Institute of Petroleum Exploration & Development (RIPED), PetroChina, Beijing 100083, China
| | - Hajime Tanaka
- Research Center for Advanced Science and Technology, The University of Tokyo, 4-6-1 Komaba, Meguro-ku, Tokyo 153-8904, Japan
- Institute of Industrial Science, The University of Tokyo, 4-6-1 Komaba, Meguro-ku, Tokyo 153-8505, Japan
| | - Georgios M Kontogeorgis
- Department of Chemical and Biochemical Engineering, Center for Energy Resources Engineering, Technical University of Denmark, Building 229, Lyngby DK-2800, Denmark
| | - Xiaodong Liang
- Department of Chemical and Biochemical Engineering, Center for Energy Resources Engineering, Technical University of Denmark, Building 229, Lyngby DK-2800, Denmark
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Novak N, Liang X, Kontogeorgis GM. Prediction of water anomalous properties by introducing the two-state theory in SAFT. J Chem Phys 2024; 160:104505. [PMID: 38465683 DOI: 10.1063/5.0186752] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2023] [Accepted: 02/14/2024] [Indexed: 03/12/2024] Open
Abstract
Water is one of the most abundant substances on earth, but it is still not entirely understood. It shows unusual behavior, and its properties present characteristic extrema unlike any other fluid. This unusual behavior has been linked to the two-state theory of water, which proposes that water forms different clusters, one with a high density and one with a low density, which may even form two distinct phases at low temperatures. Models incorporating the two-state theory manage to capture the unusual extrema of water, unlike traditional equations of state, which fail. In this work, we have derived the framework to incorporate the two-state theory of water into the Statistical-Associating-Fluid-Theory (SAFT). More specifically, we have assumed that water is an ideal solution of high density water molecules and low density water molecules that are in chemical equilibrium. Using this assumption, we have generalized the association term SAFT to allow for the simultaneous existence of the two water types, which have the same physical parameters but different association properties. We have incorporated the newly derived association term in the context of the Perturbed Chain-SAFT (PC-SAFT). The new model is referred to as PC-SAFT-Two-State (PC-SAFT-TS). Using PC-SAFT-TS, we have succeeded in predicting the characteristic extrema of water, such as its density and speed of sound maximum, etc., without loss of accuracy compared to the original PC-SAFT. This new framework is readily extended to mixtures, and PC-SAFT-TS manages to capture the solubility minimum of hydrocarbons in water in a straightforward manner.
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Affiliation(s)
- Nefeli Novak
- Center for Energy Resources Engineering, Department of Chemical and Biochemical Engineering, Technical University of Denmark, 2800 Kgs Lyngby, Denmark
| | - Xiaodong Liang
- Center for Energy Resources Engineering, Department of Chemical and Biochemical Engineering, Technical University of Denmark, 2800 Kgs Lyngby, Denmark
| | - Georgios M Kontogeorgis
- Center for Energy Resources Engineering, Department of Chemical and Biochemical Engineering, Technical University of Denmark, 2800 Kgs Lyngby, Denmark
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Foffi R, Sciortino F. Identification of local structures in water from supercooled to ambient conditions. J Chem Phys 2024; 160:094504. [PMID: 38436442 DOI: 10.1063/5.0188764] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2023] [Accepted: 02/09/2024] [Indexed: 03/05/2024] Open
Abstract
Studies of water thermodynamics have long been tied to the identification of two distinct families of local structures, whose competition could explain the origin of the many thermodynamic anomalies and the hypothesized liquid-liquid critical point in water. Despite the many successes and insights gained, the structural indicators proposed throughout the years were not able to unequivocally identify these two families over a wide range of conditions. We show that a recently introduced indicator, Ψ, which exploits information on the hydrogen bond network connectivity, can reliably identify these two distinct local environments over a wide range of thermodynamic conditions (188-300 K and 0-13 kbar) and that close to the liquid-liquid critical point, the spatial correlations of density fluctuations are identical to those of the Ψ indicator. Our results strongly support the idea that water thermodynamic properties arise from the competition between two distinct and identifiable local environments.
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Affiliation(s)
- Riccardo Foffi
- Department of Civil, Environmental and Geomatic Engineering, Institute for Environmental Engineering, ETH Zürich, Laura-Hezner-Weg 7, 8093 Zürich, Switzerland
| | - Francesco Sciortino
- Dipartimento di Fisica, Sapienza Università di Roma, Piazzale Aldo Moro 5, I-00185 Rome, Italy
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de Oliveira PMC, de Souza JIR, da Silva JAB, Longo RL. Temperature Dependence of Hydrogen Bond Networks of Liquid Water: Thermodynamic Properties and Structural Heterogeneity from Topological Descriptors. J Phys Chem B 2023; 127:2250-2257. [PMID: 36877152 DOI: 10.1021/acs.jpcb.2c08873] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/07/2023]
Abstract
Topological analyses of hydrogen bond networks were performed based on the complex network and island statistics of liquid water at different temperatures. The influence of temperature on the liquid water structures and the topological properties of the hydrogen bond networks was investigated by Metropolis Monte Carlo simulations with the TIP4P/2005 potential model. The bilinear behavior of the second peak in the radial distribution function with the temperature was properly reproduced by these simulations. The average connectivity also displayed a bilinear behavior consistent with being a local descriptor. The semiglobal average path length (or geodesic distance) descriptor showed an unprecedented trimodal distribution, whose areas were dependent on the temperature. Considering equilibrium between these three sets of networks, standard enthalpy and entropy of equilibrium were determined for the first time, providing new insights into the structural heterogeneities of liquid water with interesting perspectives for modeling these quantitative properties of hydrogen bond networks.
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Affiliation(s)
- Paulo M C de Oliveira
- Núcleo Interdisciplinar de Ciências Exatas e da Natureza, Campus do Agreste. Universidade Federal de Pernambuco, 55.014-900 Caruaru, Pernambuco, Brazil
| | - Jéssica I R de Souza
- Programa de Pós-Graduação em Ciência de Materiais, Universidade Federal de Pernambuco, 50740-560 Recife, Pernambuco, Brazil
| | - Juliana A B da Silva
- Núcleo Interdisciplinar de Ciências Exatas e da Natureza, Campus do Agreste. Universidade Federal de Pernambuco, 55.014-900 Caruaru, Pernambuco, Brazil.,Programa de Pós-Graduação em Química, Universidade Federal Rural de Pernambuco, 52.171-900 Recife, Pernambuco, Brazil
| | - Ricardo L Longo
- Programa de Pós-Graduação em Ciência de Materiais, Universidade Federal de Pernambuco, 50740-560 Recife, Pernambuco, Brazil.,Departamento de Química Fundamental, Universidade Federal de Pernambuco, 50740-540 Recife, Pernambuco, Brazil
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Foffi R, Sciortino F. Correlated Fluctuations of Structural Indicators Close to the Liquid-Liquid Transition in Supercooled Water. J Phys Chem B 2022; 127:378-386. [PMID: 36538764 PMCID: PMC9841516 DOI: 10.1021/acs.jpcb.2c07169] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
Multiple numerical studies have unambiguously shown the existence of a liquid-liquid critical point in supercooled states for different numerical models of water, and various structural indicators have been put forward to describe the transformation associated with this phase transition. Here we analyze numerical simulations of near-critical supercooled water to compare the behavior of several of such indicators with critical density fluctuations. We show that close to the critical point most indicators are strongly correlated to density, and some of them even display identical distributions of fluctuations. These indicators probe the exact same free energy landscape, therefore providing a thermodynamic description of critical supercooled water which is identical to that provided by the density order parameter. This implies that close to the critical point, there is a tight coupling between many, only apparently distinct, structural degrees of freedom.
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Affiliation(s)
- Riccardo Foffi
- Institute
for Environmental Engineering, Department of Civil, Environmental
and Geomatic Engineering, ETH Zürich, 8093Zürich, Switzerland
| | - Francesco Sciortino
- Dipartimento
di Fisica, Sapienza Università di
Roma, Piazzale Aldo Moro
5, I-00185Rome, Italy,E-mail:
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Fardis M, Karagianni M, Gkoura L, Papavassiliou G. Self-Diffusion in Confined Water: A Comparison between the Dynamics of Supercooled Water in Hydrophobic Carbon Nanotubes and Hydrophilic Porous Silica. Int J Mol Sci 2022; 23:ijms232214432. [PMID: 36430907 PMCID: PMC9697084 DOI: 10.3390/ijms232214432] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2022] [Revised: 11/15/2022] [Accepted: 11/17/2022] [Indexed: 11/22/2022] Open
Abstract
Confined liquids are model systems for the study of the metastable supercooled state, especially for bulk water, in which the onset of crystallization below 230 K hinders the application of experimental techniques. Nevertheless, in addition to suppressing crystallization, confinement at the nanoscale drastically alters the properties of water. Evidently, the behavior of confined water depends critically on the nature of the confining environment and the interactions of confined water molecules with the confining matrix. A comparative study of the dynamics of water under hydrophobic and hydrophilic confinement could therefore help to clarify the underlying interactions. As we demonstrate in this work using a few representative results from the relevant literature, the accurate assessment of the translational mobility of water molecules, especially in the supercooled state, can unmistakably distinguish between the hydrophilic and hydrophobic nature of the confining environments. Among the numerous experimental methods currently available, we selected nuclear magnetic resonance (NMR) in a field gradient, which directly measures the macroscopic translational self-diffusion coefficient, and quasi-elastic neutron scattering (QENS), which can determine the microscopic translational dynamics of the water molecules. Dielectric relaxation, which probes the re-orientational degrees of freedom, are also discussed.
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Tsochantaris E, Muthachikavil AV, Peng B, Liang X, Kontogeorgis GM. Multiple insights call for revision of modern thermodynamic models to account for structural fluctuations in water. AIChE J 2022; 68:e17891. [PMID: 36591369 PMCID: PMC9787682 DOI: 10.1002/aic.17891] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2022] [Revised: 06/29/2022] [Accepted: 08/15/2022] [Indexed: 01/04/2023]
Abstract
Modern thermodynamic models incorporate the concept of association (hydrogen bonding) and they can describe very satisfactorily many properties of water containing mixtures. They have not been successful in representing water's anomalous properties and this work provides a possible explanation. We have analyzed and interpreted recent experimental data, molecular simulation results, and two-state theory approaches and compared against the predictions from thermodynamic models. We show that the dominance of the tetrahedral structure implemented in modern thermodynamic models may be the reason for their failure for describing water systems. While this study does not prove the two-state theories for water, it indicates that a high level of tetrahedral structure of water is not in agreement with water's anomalous properties when used in thermodynamic models.
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Affiliation(s)
- Evangelos Tsochantaris
- Department of Chemical and Biochemical Engineering, Center for Energy Resources EngineeringTechnical University of DenmarkLyngbyDenmark
| | - Aswin V. Muthachikavil
- Department of Chemical and Biochemical Engineering, Center for Energy Resources EngineeringTechnical University of DenmarkLyngbyDenmark
| | - Baoliang Peng
- Research Institute of Petroleum Exploration & Development (RIPED), PetroChinaBeijingChina
| | - Xiaodong Liang
- Department of Chemical and Biochemical Engineering, Center for Energy Resources EngineeringTechnical University of DenmarkLyngbyDenmark
| | - Georgios M. Kontogeorgis
- Department of Chemical and Biochemical Engineering, Center for Energy Resources EngineeringTechnical University of DenmarkLyngbyDenmark
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