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Li X, Jin Y. Thermodynamic crossovers in supercritical fluids. Proc Natl Acad Sci U S A 2024; 121:e2400313121. [PMID: 38652745 PMCID: PMC11067041 DOI: 10.1073/pnas.2400313121] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2024] [Accepted: 03/26/2024] [Indexed: 04/25/2024] Open
Abstract
Can liquid-like and gas-like states be distinguished beyond the critical point, where the liquid-gas phase transition no longer exists and conventionally only a single supercritical fluid phase is defined? Recent experiments and simulations report strong evidence of dynamical crossovers above the critical temperature and pressure. Despite using different criteria, many existing theoretical explanations consider a single crossover line separating liquid-like and gas-like states in the supercritical fluid phase. We argue that such a single-line scenario is inconsistent with the supercritical behavior of the Ising model, which has two crossover lines due to its symmetry, violating the universality principle of critical phenomena. To reconcile the inconsistency, we define two thermodynamic crossover lines in supercritical fluids as boundaries of liquid-like, indistinguishable, and gas-like states. Near the critical point, the two crossover lines follow critical scalings with exponents of the Ising universality class, supported by calculations of theoretical models and analyses of experimental data from the standard database. The upper line agrees with crossovers independently estimated from the inelastic X-ray scattering data of supercritical argon, and from the small-angle neutron scattering data of supercritical carbon dioxide. The lower line is verified by the equation of states for the compressibility factor. This work provides a fundamental framework for understanding supercritical physics in general phase transitions.
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Affiliation(s)
- Xinyang Li
- Institute of Theoretical Physics, Chinese Academy of Sciences, Beijing100190, China
- School of Physical Sciences, University of Chinese Academy of Sciences, Beijing100049, China
| | - Yuliang Jin
- Institute of Theoretical Physics, Chinese Academy of Sciences, Beijing100190, China
- School of Physical Sciences, University of Chinese Academy of Sciences, Beijing100049, China
- Center for Theoretical Interdisciplinary Sciences, Wenzhou Institute, University of Chinese Academy of Sciences, Wenzhou, Zhejiang325001, China
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2
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Ojovan MI, Louzguine-Luzgin DV. The Minima of Viscosities. MATERIALS (BASEL, SWITZERLAND) 2024; 17:1822. [PMID: 38673178 PMCID: PMC11051500 DOI: 10.3390/ma17081822] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/25/2024] [Revised: 04/04/2024] [Accepted: 04/10/2024] [Indexed: 04/28/2024]
Abstract
The Trachenko-Brazhkin equation of the minimal possible viscosity is analysed, emphasising its validity by the account of multibody interactions between flowing species through some effective masses replacing their true (bare) masses. Pressure affects the effective masses, decreasing them and shifting the minimal viscosity and the temperature at which it is attained to higher values. The analysis shows that effective masses in the Trachenko-Brazhkin equation are typically lighter compared bare masses; e.g., for tin (Sn) the effective mass is m = 0.21mSn, whereas for supercritical argon (Ar), it changes from m = 0.165mAr to m = 0.129mAr at the pressures of 20 and 100 MPa, respectively.
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Affiliation(s)
- Michael I. Ojovan
- Department of Materials, Imperial College London, South Kensington Campus, Exhibition Road, London SW7 2AZ, UK
- Department of Materials Science and Engineering, The University of Sheffield, Sir Robert Hadfield Building, Mappin Street, Sheffield S1 3JD, UK
- Advanced Institute for Materials Research (WPI-AIMR), Tohoku University, Aoba-Ku, Sendai 980-8577, Japan;
| | - Dmitri V. Louzguine-Luzgin
- Advanced Institute for Materials Research (WPI-AIMR), Tohoku University, Aoba-Ku, Sendai 980-8577, Japan;
- MathAM-OIL, National Institute of Advanced Industrial Science and Technology (AIST), Sendai 980-8577, Japan
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3
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Simeski F, Ihme M. Supercritical fluids behave as complex networks. Nat Commun 2023; 14:1996. [PMID: 37032390 PMCID: PMC10083177 DOI: 10.1038/s41467-023-37645-z] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2022] [Accepted: 03/22/2023] [Indexed: 04/11/2023] Open
Abstract
Supercritical fluids play a key role in environmental, geological, and celestial processes, and are of great importance to many scientific and engineering applications. They exhibit strong variations in thermodynamic response functions, which has been hypothesized to stem from the microstructural behavior. However, a direct connection between thermodynamic conditions and the microstructural behavior, as described by molecular clusters, remains an outstanding issue. By utilizing a first-principles-based criterion and self-similarity analysis, we identify energetically localized molecular clusters whose size distribution and connectivity exhibit self-similarity in the extended supercritical phase space. We show that the structural response of these clusters follows a complex network behavior whose dynamics arises from the energetics of isotropic molecular interactions. Furthermore, we demonstrate that a hidden variable network model can accurately describe the structural and dynamical response of supercritical fluids. These results highlight the need for constitutive models and provide a basis to relate the fluid microstructure to thermodynamic response functions.
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Affiliation(s)
- Filip Simeski
- Department of Mechanical Engineering, Stanford University, Stanford, CA, 94305, USA
| | - Matthias Ihme
- Department of Mechanical Engineering, Stanford University, Stanford, CA, 94305, USA.
- Department of Photon Science, SLAC National Accelerator Laboratory, Menlo Park, CA, 94025, USA.
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4
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Pruteanu CG, Bannerman MN, Kirsz M, Lue L, Ackland GJ. From Atoms to Colloids: Does the Frenkel Line Exist in Discontinuous Potentials? ACS OMEGA 2023; 8:12144-12153. [PMID: 37033816 PMCID: PMC10077443 DOI: 10.1021/acsomega.2c08056] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 12/19/2022] [Accepted: 03/20/2023] [Indexed: 06/19/2023]
Abstract
The Frenkel line has been proposed as a crossover in the fluid region of phase diagrams between a "nonrigid" and a "rigid" fluid. It is generally described as a crossover in the dynamical properties of a material and as such has been described theoretically using a very different set of markers from those with which is it investigated experimentally. In this study, we have performed extensive calculations using two simple yet fundamentally different model systems: hard spheres and square-well potentials. The former has only hardcore repulsion, while the latter also includes a simple model of attraction. We computed and analyzed a series of physical properties used previously in simulations and experimental measurements and discuss critically their correlations and validity as to being able to uniquely and coherently locate the Frenkel line in discontinuous potentials.
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Affiliation(s)
- Ciprian G. Pruteanu
- SUPA,
School of Physics and Astronomy and Centre for Science at Extreme
Conditions, The University of Edinburgh, Edinburgh EH9 3JZ, United Kingdom
| | - Marcus N. Bannerman
- School
of Engineering, University of Aberdeen, Aberdeen AB24 3UE, United Kingdom
| | - Marcin Kirsz
- SUPA,
School of Physics and Astronomy and Centre for Science at Extreme
Conditions, The University of Edinburgh, Edinburgh EH9 3JZ, United Kingdom
| | - Leo Lue
- Department
of Chemical and Process Engineering, University
of Strathclyde, James
Weir Building, 75 Montrose Street, Glasgow G1 1XJ, United
Kingdom
| | - Graeme J. Ackland
- SUPA,
School of Physics and Astronomy and Centre for Science at Extreme
Conditions, The University of Edinburgh, Edinburgh EH9 3JZ, United Kingdom
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5
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Kinnun JJ, Scott HL, Bolmatov D, Collier CP, Charlton TR, Katsaras J. Biophysical studies of lipid nanodomains using different physical characterization techniques. Biophys J 2023; 122:931-949. [PMID: 36698312 PMCID: PMC10111277 DOI: 10.1016/j.bpj.2023.01.024] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2022] [Revised: 01/12/2023] [Accepted: 01/19/2023] [Indexed: 01/26/2023] Open
Abstract
For the past 50 years, evidence for the existence of functional lipid domains has been steadily accumulating. Although the notion of functional lipid domains, also known as "lipid rafts," is now widely accepted, this was not always the case. This ambiguity surrounding lipid domains could be partly attributed to the fact that they are highly dynamic, nanoscopic structures. Since most commonly used techniques are sensitive to microscale structural features, it is therefore, not surprising that it took some time to reach a consensus regarding their existence. In this review article, we will discuss studies that have used techniques that are inherently sensitive to nanoscopic structural features (i.e., neutron scatting, nuclear magnetic resonance, and Förster resonance energy transfer). We will also mention techniques that may be of use in the future (i.e., cryoelectron microscopy, droplet interface bilayers, inelastic x-ray scattering, and neutron reflectometry), which can further our understanding of the different and unique physicochemical properties of nanoscopic lipid domains.
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Affiliation(s)
- Jacob J Kinnun
- Large Scale Structures Group, Neutron Scattering Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee; Shull Wollan Center, Oak Ridge National Laboratory, Oak Ridge, Tennessee.
| | - Haden L Scott
- Large Scale Structures Group, Neutron Scattering Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee; Shull Wollan Center, Oak Ridge National Laboratory, Oak Ridge, Tennessee
| | - Dima Bolmatov
- Shull Wollan Center, Oak Ridge National Laboratory, Oak Ridge, Tennessee; Department of Physics and Astronomy, University of Tennessee, Knoxville, Tennessee
| | - C Patrick Collier
- Center for Nanophase Materials Sciences, Oak Ridge National Laboratory, Oak Ridge, Tennessee
| | - Timothy R Charlton
- Large Scale Structures Group, Neutron Scattering Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee
| | - John Katsaras
- Shull Wollan Center, Oak Ridge National Laboratory, Oak Ridge, Tennessee; Department of Physics and Astronomy, University of Tennessee, Knoxville, Tennessee; Labs and Soft Matter Group, Neutron Scattering Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee.
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6
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Bolmatov D. The Phonon Theory of Liquids and Biological Fluids: Developments and Applications. J Phys Chem Lett 2022; 13:7121-7129. [PMID: 35950307 DOI: 10.1021/acs.jpclett.2c01779] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
Among the three basic states of matter (solid, liquid, and gas), the liquid state has always eluded general theoretical approaches for describing liquid energy and heat capacity. In this Viewpoint, we derive the phonon theory of liquids and biological fluids stemming from Frenkel's microscopic picture of the liquid state. Specifically, the theory predicts the existence of phonon gaps in vibrational spectra of liquids and a thermodynamic boundary in the supercritical state. Direct experimental evidence reaffirming these theoretical predictions was achieved through a combination of techniques using static compression X-ray diffraction and inelastic X-ray scattering on deeply supercritical argon in a diamond anvil cell. Furthermore, these findings inspired and then led to the discovery of phonon gaps in liquid crystals (mesogens), block copolymers, and biological membranes. Importantly, phonon gaps define viscoelastic crossovers in cellular membranes responsible for lipid self-diffusion, lateral molecular-level stress propagation, and passive transmembrane transport of small molecules and solutes. Finally, molecular interactions mediated by external stimuli result in synaptic activity controlling biological membranes' plasticity resulting in learning and memory. Therefore, we also discuss learning and memory effects─equally important for neuroscience as well as for the development of neuromorphic devices─facilitated in biological membranes by external stimuli.
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Affiliation(s)
- Dima Bolmatov
- Department of Physics and Astronomy, University of Tennessee, Knoxville, Tennessee 37996, United States
- Shull Wollan Center, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, United States
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7
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8
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Pruteanu CG, Kirsz M, Ackland GJ. Frenkel Line in Nitrogen Terminates at the Triple Point. J Phys Chem Lett 2021; 12:11609-11615. [PMID: 34812632 DOI: 10.1021/acs.jpclett.1c03206] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
Recent studies on supercritical nitrogen revealed clear changes in structural markers and dynamical properties when the coordination number approaches its maximum value. The line in P and T space where these changes occur is referred to as the Frenkel line. Here, we qualitatively reproduce such changes in the supercritical regime using the popular "optimized potential for liquid simulation" (OPLS) classical force field for molecular dynamics. Unfortunately, at 160 K, OPLS nitrogen predicts sublimation rather than producing a liquid phase; therefore, we developed our own force field to achieve quantitative agreement with experimental data. We confirm the asymptotic behavior of the coordination number on crossing the Frenkel line and note an associated change in the diffusion constant, consistent with the non-rigid to rigid liquid-like character of the "transition". The simulations allow us to track the Frenkel line to subcritical temperatures and demonstrate that it terminates at the triple point. This establishes the experimentally measurable changes, which could unequivocally determine the Frenkel line in other systems.
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Affiliation(s)
- Ciprian G Pruteanu
- Scottish Universities Physics Alliance (SUPA), School of Physics and Astronomy and Centre for Science at Extreme Conditions, The University of Edinburgh, Edinburgh EH9 3FD, United Kingdom
| | - Marcin Kirsz
- Scottish Universities Physics Alliance (SUPA), School of Physics and Astronomy and Centre for Science at Extreme Conditions, The University of Edinburgh, Edinburgh EH9 3FD, United Kingdom
| | - Graeme J Ackland
- Scottish Universities Physics Alliance (SUPA), School of Physics and Astronomy and Centre for Science at Extreme Conditions, The University of Edinburgh, Edinburgh EH9 3FD, United Kingdom
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9
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Skarmoutsos I, Henao A, Guardia E, Samios J. On the Different Faces of the Supercritical Phase of Water at a Near-Critical Temperature: Pressure-Induced Structural Transitions Ranging from a Gaslike Fluid to a Plastic Crystal Polymorph. J Phys Chem B 2021; 125:10260-10272. [PMID: 34491748 DOI: 10.1021/acs.jpcb.1c05053] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The present study reports a systematic analysis of a wide variety of structural, thermodynamic, and dynamic properties of supercritical water along the near-critical isotherm of T = 1.03Tc and up to extreme pressures, using molecular dynamics and Monte Carlo simulations. The methodology employed provides solid evidence about the existence of a structural transition from a liquidlike fluid to a compressed, tightly packed liquid, in the density and pressure region around 3.4ρc and 1.17 GPa, introducing an alternative approach to locate the crossing of the Frenkel line. Around 8.5 GPa another transition to a face-centered-cubic plastic crystal polymorph with density 5.178ρc is also observed, further confirmed by Gibbs free energy calculations using the two-phase thermodynamic model. The isobaric heat capacity maximum, closely related to the crossing of the Widom line, has also been observed around 0.8ρc, where the local density augmentation is also maximized. Another structural transition has been observed at 0.2ρc, related to the transformation of the fluid to a dilute gas at lower densities. These findings indicate that a near-critical isotherm can be divided into different domains where supercritical water exhibits distinct behavior, ranging from a gaslike one to a plastic crystal one.
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Affiliation(s)
- Ioannis Skarmoutsos
- Theoretical and Physical Chemistry Institute, National Hellenic Research Foundation, Vas. Constantinou 48, GR-116 35, Athens, Greece
| | - Andrés Henao
- Dynamics of Condensed Matter and Center for Sustainable Systems Design, Department of Chemistry, University of Paderborn, Warburger Strasse 100, D-33098 Paderborn, Germany
| | - Elvira Guardia
- Departament de Física, Universitat Politècnica de Catalunya, Campus Nord-Edifici B4-B5, Jordi Girona 1-3, Barcelona E-08034, Spain
| | - Jannis Samios
- Department of Chemistry, Laboratory of Physical Chemistry, National and Kapodistrian University of Athens, Panepistimiopolis GR-157 71, Athens, Greece
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10
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The Anomalous Behavior of Thermodynamic Parameters in the Three Widom Deltas of Carbon Dioxide-Ethanol Mixture. Int J Mol Sci 2021; 22:ijms22189813. [PMID: 34575970 PMCID: PMC8472178 DOI: 10.3390/ijms22189813] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2021] [Revised: 09/07/2021] [Accepted: 09/08/2021] [Indexed: 11/23/2022] Open
Abstract
Using molecular dynamics, we demonstrated that in the mixture of carbon dioxide and ethanol (25% molar fraction) there are three pronounced regions on the p-T diagram characterized by not only high-density fluctuations but also anomalous behavior of thermodynamic parameters. The regions are interpreted as Widom deltas. The regions were identified as a result of analyzing the dependences of density, density fluctuations, isobaric thermal conductivity, and clustering of a mixture of carbon dioxide and ethanol in a wide range of pressures and temperatures. Two of the regions correspond to the Widom delta for pure supercritical carbon dioxide and ethanol, while the third region is in the immediate vicinity of the critical point of the binary mixture. The origin of these Widom deltas is a result of the large mixed linear clusters formation.
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11
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Xu J, Wang Y, Ma X. Phase distribution including a bubblelike region in supercritical fluid. Phys Rev E 2021; 104:014142. [PMID: 34412334 DOI: 10.1103/physreve.104.014142] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2021] [Accepted: 07/02/2021] [Indexed: 11/07/2022]
Abstract
Pseudoboiling in supercritical fluid (SF) has been paid great attention in recent years. Available works mainly focus on thermodynamics analysis. Fewer studies were reported on the spatial time phase distribution. Here, SF is investigated in a multiphase fluid framework using molecular dynamics (MD) simulations. A simulation box contains 10 976 argon atoms, with periodic boundary conditions applied on all the box surfaces. Pressure and temperature are well controlled. Based on MD simulation results, an onset pseudoboiling temperature T^{-} and a termination pseudoboiling temperature T^{+} are defined using the neighboring molecules method, the radial distribution function method, and the two-body excess entropy method. The two transition temperatures divide the whole phase diagram into three regimes of liquidlike, two-phase-like (TPL), and gaslike, and the MD determined T^{-} and T^{+} well matched the thermodynamics-determined values. In the TPL regime, nanovoids are observed to have two distinct characteristics: (1) Particles are sparsely distributed to have gas density inside the void, but are densely populated to have liquid density outside the void. (2) Voids have a curved interface. These characteristics are very similar to bubble characteristics in subcritical pressure. Hence, voids in the supercritical state are called "bubblelike" in this paper. Nonlinear dynamics demonstrates chaotic behavior in the TPL regime, similar to the two-phase regime in the subcritical domain. The above findings give strong evidence that SF in the TPL regime consists of a mixture of bubblelike voids and surrounding liquids. Our work highlights the multiphase feature of a SF, hence, the well-established multiphase theory in subcritical pressures can be introduced to handle the complex SF.
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Affiliation(s)
- Jinliang Xu
- Beijing Key Laboratory of Multiphase Flow and Heat Transfer for Low Grade Energy Utilization, North China Electric Power University, Beijing, 102206, China.,Key Laboratory of Power Station Energy Transfer Conversion and System, North China Electric Power University, Ministry of Education, Beijing, 102206, China
| | - Yan Wang
- Beijing Key Laboratory of Multiphase Flow and Heat Transfer for Low Grade Energy Utilization, North China Electric Power University, Beijing, 102206, China
| | - Xiaojing Ma
- Beijing Key Laboratory of Multiphase Flow and Heat Transfer for Low Grade Energy Utilization, North China Electric Power University, Beijing, 102206, China
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12
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Bell IH, Delage-Santacreu S, Hoang H, Galliero G. Dynamic Crossover in Fluids: From Hard Spheres to Molecules. J Phys Chem Lett 2021; 12:6411-6417. [PMID: 34232673 DOI: 10.1021/acs.jpclett.1c01594] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
We propose a simple and generic definition of a demarcation reconciling structural and dynamic frameworks when combined with the entropy scaling framework. This crossover line between gas- and liquid-like behaviors is defined as the curve for which an individual property, the contribution to viscosity due to molecules' translation, is exactly equal to a collective property, the contribution to viscosity due to molecular interactions. Such a definition is shown to be consistent with the one based on the minima of the kinematic viscosity. For the hard sphere, this is shown to be an exact solution. For Lennard-Jones spheres and dimers and for some simple real fluids, this relation holds very well. This crossover line passes nearby the critical point, and for all studied fluids, it is well captured by the critical excess entropy curve for atomic fluids, emphasizing the link between transport properties and local structure.
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Affiliation(s)
- Ian H Bell
- Applied Chemicals and Materials Division, National Institute of Standards and Technology, Boulder, Colorado 80305, United States
| | - Stéphanie Delage-Santacreu
- Université de Pau et des Pays de l'Adour, e2s UPPA, Laboratoire de Mathematiques et de leurs Applications de Pau (IPRA, CNRS UMR5142), Pau 64000, France
| | - Hai Hoang
- Institute of Fundamental and Applied Sciences, Duy Tan University, 10C Tran Nhat Duat Street, District 1, Ho Chi Minh City 700000, Vietnam
- Faculty of Natural Sciences, Duy Tan University, Da Nang 550000, Vietnam
| | - Guillaume Galliero
- Université de Pau et des Pays de l'Adour, e2s UPPA, TOTAL, CNRS, LFCR, UMR 5150, Laboratoire des fluides complexes et leurs reservoirs, Pau 64000, France
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13
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Chatwell RS, Guevara-Carrion G, Gaponenko Y, Shevtsova V, Vrabec J. Diffusion of the carbon dioxide-ethanol mixture in the extended critical region. Phys Chem Chem Phys 2021; 23:3106-3115. [PMID: 33491706 DOI: 10.1039/d0cp04985a] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The effect of traces of ethanol in supercritical carbon dioxide on the mixture's thermodynamic properties is studied by molecular simulations and Taylor dispersion measurements. This mixture is investigated along the isobar p = 10 MPa in the temperature range between T = 304 and 343 K. Along this path, the mixture undergoes two transitions: First, the Widom line is crossed, marking the transition from liquid-like to gas-like conditions. A second transition occurs from the supercritical gas-like domain to a subcritical gas. The Widom line crossover entails inflection points for most of the studied properties, i.e. density, enthalpy, shear viscosity, Maxwell-Stefan and intradiffusion coefficients. On the other hand, the transition between the super- and subcritical regions is found to be generally smooth, an observation that is qualitatively confirmed by experimental Taylor dispersion measurements. Dedicated atomistic simulations show the presence of microheterogeneities due to ethanol self-association along the investigated path, which lead to the mixture's anomalous behavior in its extended critical region.
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Affiliation(s)
- René Spencer Chatwell
- Thermodynamics and Process Engineering, Technische Universität Berlin, 10587 Berlin, Germany.
| | | | - Yuri Gaponenko
- Microgravity Research Center, Université Libre de Bruxelles, 1050 Bruxelles, Belgium
| | - Valentina Shevtsova
- Microgravity Research Center, Université Libre de Bruxelles, 1050 Bruxelles, Belgium
| | - Jadran Vrabec
- Thermodynamics and Process Engineering, Technische Universität Berlin, 10587 Berlin, Germany.
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14
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Banuti D, Raju M, Ihme M. Between supercritical liquids and gases – Reconciling dynamic and thermodynamic state transitions. J Supercrit Fluids 2020. [DOI: 10.1016/j.supflu.2020.104895] [Citation(s) in RCA: 27] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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15
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Pipich V, Schwahn D. Polymorphic phase transition in liquid and supercritical carbon dioxide. Sci Rep 2020; 10:11861. [PMID: 32681012 PMCID: PMC7367860 DOI: 10.1038/s41598-020-68451-y] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2020] [Accepted: 06/16/2020] [Indexed: 12/02/2022] Open
Abstract
We present experiments on molecular density fluctuations in liquid and supercritical (SC) CO2 using small-angle neutron scattering. Thermal density fluctuations in SC-CO2 determine susceptibility and correlation length identifying the Widom line at their maxima. Droplet formation occurs at the gas–liquid line and between 20 and 60 bar above the Widom line, the corresponding borderline identified as the Frenkel line. The droplets start to form spheres of constant radius of ≈ 45 Å and transform into rods and globules at higher pressure. Droplet formation represents a liquid–liquid (polymorphic) phase transition of the same composition but different density, whose difference defines its order parameter. Polymorphism in CO2 is a new observation stimulating interesting discussions on the topics of gas-like to liquid-like transition in SC fluids and polymorphism since CO2 represents a “simple” van der Waals liquid in contrast to water, which is the most widely studied liquid showing polymorphism in its supercooled state.
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Affiliation(s)
- Vitaliy Pipich
- Forschungszentrum Jülich GmbH, Jülich Centre for Neutron Science (JCNS) at Heinz Maier-Leibnitz Zentrum (MLZ), Lichtenbergstraße 1, 85748, Garching, Germany
| | - Dietmar Schwahn
- Forschungszentrum Jülich GmbH, Jülich Centre for Neutron Science (JCNS-1), Wilhelm Johnen Strasse, D-52428, Jülich, Germany.
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16
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Brown OCF, Vrinceanu D, Kharchenko V, Sadeghpour HR. Formation of argon cluster with proton seeding. Mol Phys 2020. [DOI: 10.1080/00268976.2020.1767813] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
Affiliation(s)
- O. C. F. Brown
- ITAMP, Harvard-Smithsonian Center for Astrophysics, Cambridge, MA, USA
- Department of Physics and Astronomy, University of Southampton, Southampton, UK
| | - D. Vrinceanu
- Department of Physics, Texas Southern University, Houston, TX, USA
| | - V. Kharchenko
- ITAMP, Harvard-Smithsonian Center for Astrophysics, Cambridge, MA, USA
- Department of Physics, University of Connecticut, Storrs, CT, USA
| | - H. R. Sadeghpour
- ITAMP, Harvard-Smithsonian Center for Astrophysics, Cambridge, MA, USA
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17
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Ha MY, Yoon TJ, Tlusty T, Jho Y, Lee WB. Universality, Scaling, and Collapse in Supercritical Fluids. J Phys Chem Lett 2020; 11:451-455. [PMID: 31878784 DOI: 10.1021/acs.jpclett.9b03360] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Supercritical fluid (SCF) is known to exhibit salient dynamic and thermodynamic crossovers and an inhomogeneous molecular distribution. However, the question as to what basic physics underlies these microscopic and macroscopic anomalies remains open. Here, using an order parameter extracted by machine learning, the fraction of gas-like (or liquid-like) molecules, we find simplicity and universality in SCF: First, all isotherms of a given fluid collapse onto a single master curve described by a scaling relation. The observed power law holds from the high-temperature and -pressure regime down to the critical point where it diverges. Second, phase diagrams of different compounds collapse onto their master curves by the same scaling exponent, thereby demonstrating a putative law of corresponding supercritical states in simple fluids. The reported results support a model of the SCF as a mixture of two interchangeable microstates, whose spatiotemporal dynamics gives rise to unique macroscopic properties.
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Affiliation(s)
- Min Young Ha
- School of Chemical and Biological Engineering, Institute of Chemical Processes , Seoul National University , Seoul 08826 , Republic of Korea
| | - Tae Jun Yoon
- School of Chemical and Biological Engineering, Institute of Chemical Processes , Seoul National University , Seoul 08826 , Republic of Korea
| | - Tsvi Tlusty
- Center for Soft and Living Matter , Institute for Basic Science (IBS) , Ulsan 44919 , Republic of Korea
- Department of Physics , Ulsan National Institute of Science and Technology (UNIST) , Ulsan 44919 , Republic of Korea
| | - YongSeok Jho
- Department of Physics and Research Institute of Natural Science , Gyeongsang National University , Jinju 52828 , Republic of Korea
| | - Won Bo Lee
- School of Chemical and Biological Engineering, Institute of Chemical Processes , Seoul National University , Seoul 08826 , Republic of Korea
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18
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Proctor JE, Pruteanu CG, Morrison I, Crowe IF, Loveday JS. Transition from Gas-like to Liquid-like Behavior in Supercritical N 2. J Phys Chem Lett 2019; 10:6584-6589. [PMID: 31604009 DOI: 10.1021/acs.jpclett.9b02358] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
We have studied in detail the transition from gas-like to rigid liquid-like behavior in supercritical N2 at 300 K (2.4 TC). Our study combines neutron diffraction and Raman spectroscopy with ab initio molecular dynamics simulations. We observe a narrow transition from gas-like to rigid liquid-like behavior at ca. 150 MPa, which we associate with the Frenkel line. Our findings allow us to reliably characterize the Frenkel line using both diffraction and spectroscopy methods, backed up by simulation, for the same substance. We clearly lay out what parameters change, and what parameters do not change, when the Frenkel line is crossed.
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Affiliation(s)
- J E Proctor
- Materials and Physics Research Group , University of Salford , Manchester M5 4WT , U.K
| | - C G Pruteanu
- Department of Physics and Astronomy , University College London , Gower Street , London WC1E 6BT , U.K
| | - I Morrison
- Materials and Physics Research Group , University of Salford , Manchester M5 4WT , U.K
| | - I F Crowe
- Photon Science Institute and School of Electrical and Electronic Engineering , University of Manchester , Oxford Road , Manchester M13 9PL , U.K
| | - J S Loveday
- SUPA, School of Physics and Astronomy and Centre for Science at Extreme Conditions , The University of Edinburgh , Edinburgh EH9 3JZ , U.K
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19
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Bolmatov D, McClintic WT, Taylor G, Stanley CB, Do C, Collier CP, Leonenko Z, Lavrentovich MO, Katsaras J. Deciphering Melatonin-Stabilized Phase Separation in Phospholipid Bilayers. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2019; 35:12236-12245. [PMID: 31469572 DOI: 10.1021/acs.langmuir.9b01534] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Lipid bilayers are fundamental building blocks of cell membranes, which contain the machinery needed to perform a range of biological functions, including cell-cell recognition, signal transduction, receptor trafficking, viral budding, and cell fusion. Importantly, many of these functions are thought to take place in the laterally phase-separated regions of the membrane, commonly known as lipid rafts. Here, we provide experimental evidence for the "stabilizing" effect of melatonin, a naturally occurring hormone produced by the brain's pineal gland, on phase-separated model membranes mimicking the outer leaflet of plasma membranes. Specifically, we show that melatonin stabilizes the liquid-ordered/liquid-disordered phase coexistence over an extended range of temperatures. The melatonin-mediated stabilization effect is observed in both nanometer- and micrometer-sized liposomes using small angle neutron scattering (SANS), confocal fluorescence microscopy, and differential scanning calorimetry. To experimentally detect nanoscopic domains in 50 nm diameter phospholipid vesicles, we developed a model using the Landau-Brazovskii approach that may serve as a platform for detecting the existence of nanoscopic lateral heterogeneities in soft matter and biological materials with spherical and planar geometries.
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20
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21
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Yoon TJ, Ha MY, Lee WB, Lee YW, Lazar EA. Topological generalization of the rigid-nonrigid transition in soft-sphere and hard-sphere fluids. Phys Rev E 2019; 99:052603. [PMID: 31212432 DOI: 10.1103/physreve.99.052603] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2018] [Indexed: 06/09/2023]
Abstract
A fluid particle changes its dynamics from diffusive to oscillatory as the system density increases up to the melting density. Hence the notion of the Frenkel line was introduced to demarcate the fluid region into rigid and nonrigid liquid subregions based on the collective particle dynamics. In this work, we apply a topological framework to locate the Frenkel lines of the soft-sphere and the hard-sphere models relying on the system configurations. The topological characteristics of the ideal gas and the maximally random jammed state are first analyzed, then the classification scheme designed in our earlier work is applied to soft-sphere and hard-sphere fluids. The dependence of the classification result on the bulk density is understood based on the theory of fluid polyamorphism. The percolation behavior of solid-like clusters is described based on the fraction of solid-like molecules in an integrated manner. The crossover densities are obtained by examining the percolation of solid-like clusters. The resultant crossover densities of soft-sphere fluids converge to that of hard-sphere fluid. Hence the topological method successfully highlights the generality of the Frenkel line.
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Affiliation(s)
- Tae Jun Yoon
- School of Chemical and Biological Engineering, Institute of Chemical Processes, Seoul National University, Seoul 08826, Republic of Korea
| | - Min Young Ha
- School of Chemical and Biological Engineering, Institute of Chemical Processes, Seoul National University, Seoul 08826, Republic of Korea
| | - Won Bo Lee
- School of Chemical and Biological Engineering, Institute of Chemical Processes, Seoul National University, Seoul 08826, Republic of Korea
| | - Youn-Woo Lee
- School of Chemical and Biological Engineering, Institute of Chemical Processes, Seoul National University, Seoul 08826, Republic of Korea
| | - Emanuel A Lazar
- Department of Mathematics, Bar-Ilan University, Ramat Gan 5290002, Israel
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22
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De S, Aluru NR. Anomalous scaling of flexural phonon damping in nanoresonators with confined fluid. MICROSYSTEMS & NANOENGINEERING 2019; 5:2. [PMID: 31057929 PMCID: PMC6330506 DOI: 10.1038/s41378-018-0041-2] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 05/12/2018] [Revised: 10/17/2018] [Accepted: 11/05/2018] [Indexed: 06/09/2023]
Abstract
Various one and two-dimensional (1D and 2D) nanomaterials and their combinations are emerging as next-generation sensors because of their unique opto-electro-mechanical properties accompanied by large surface-to-volume ratio and high quality factor. Though numerous studies have demonstrated an unparalleled sensitivity of these materials as resonant nanomechanical sensors under vacuum isolation, an assessment of their performance in the presence of an interacting medium like fluid environment is scarce. Here, we report the mechanical damping behavior of a 1D single-walled carbon nanotube (SWCNT) resonator operating in the fundamental flexural mode and interacting with a fluid environment, where the fluid is placed either inside or outside of the SWCNT. A scaling study of dissipation shows an anomalous behavior in case of interior fluid where the dissipation is found to be extremely low and scaling inversely with the fluid density. Analyzing the sources of dissipation reveals that (i) the phonon dissipation remains unaltered with fluid density and (ii) the anomalous dissipation scaling in the fluid interior case is solely a characteristic of the fluid response under confinement. Using linear response theory, we construct a fluid damping kernel which characterizes the hydrodynamic force response due to the resonant motion. The damping kernel-based analysis shows that the unexpected behavior stems from time dependence of the hydrodynamic response under nanoconfinement. Our systematic dissipation analysis helps us to infer the origin of the intrinsic dissipation. We also emphasize on the difference in dissipative response of the fluid under nanoconfinement when compared to a fluid exterior case. Our finding highlights a unique feature of confined fluid-structure interaction and evaluates its effect on the performance of high-frequency nanoresonators.
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Affiliation(s)
- Subhadeep De
- Department of Mechanical Science and Engineering, University of Illinois at Urbana-Champaign, Urbana, IL 61801 USA
| | - Narayana R. Aluru
- Department of Mechanical Science and Engineering, University of Illinois at Urbana-Champaign, Urbana, IL 61801 USA
- Beckman Institute for Advanced Science and Technology, University of Illinois at Urbana-Champaign, Urbana, IL 61801 USA
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23
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Takemoto A, Kinugawa K. Quantumness and state boundaries hidden in supercritical helium-4: A path integral centroid molecular dynamics study. J Chem Phys 2018; 149:204504. [DOI: 10.1063/1.5053988] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Affiliation(s)
- Ayumi Takemoto
- Division of Chemistry, Graduate School of Humanities and Sciences, Nara Women’s University, Nara 630-8506, Japan
| | - Kenichi Kinugawa
- Division of Chemistry, Graduate School of Humanities and Sciences, Nara Women’s University, Nara 630-8506, Japan
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24
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Abstract
The Frenkel line, a crossover line between rigid and nonrigid dynamics of fluid particles, has recently been the subject of intense debate regarding its relevance as a partitioning line of the supercritical phase, where the main criticism comes from the theoretical treatment of collective particle dynamics. From an independent point of view, this Letter suggests that the two-phase thermodynamics model may alleviate this contentious situation. The model offers new criteria for defining the Frenkel line in the supercritical region and builds a robust connection among the preexisting, seemingly inconsistent definitions. In addition, one of the dynamic criteria locates the rigid-nonrigid transition of the soft-sphere and the hard-sphere models. Hence, we suggest the Frenkel line be considered as a dynamic rigid-nonrigid fluid boundary, without any relation to gas-liquid transition. These findings provide an integrative viewpoint combining fragmentized definitions of the Frenkel line, allowing future studies to be carried out in a more reliable manner.
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Affiliation(s)
- Tae Jun Yoon
- School of Chemical and Biological Engineering, Institute of Chemical Processes , Seoul National University , Seoul 08826 , Republic of Korea
| | - Min Young Ha
- School of Chemical and Biological Engineering, Institute of Chemical Processes , Seoul National University , Seoul 08826 , Republic of Korea
| | - Won Bo Lee
- School of Chemical and Biological Engineering, Institute of Chemical Processes , Seoul National University , Seoul 08826 , Republic of Korea
| | - Youn-Woo Lee
- School of Chemical and Biological Engineering, Institute of Chemical Processes , Seoul National University , Seoul 08826 , Republic of Korea
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25
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Mausbach P, Köster A, Vrabec J. Liquid state isomorphism, Rosenfeld-Tarazona temperature scaling, and Riemannian thermodynamic geometry. Phys Rev E 2018; 97:052149. [PMID: 29906919 DOI: 10.1103/physreve.97.052149] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2018] [Indexed: 11/07/2022]
Abstract
Aspects of isomorph theory, Rosenfeld-Tarazona temperature scaling, and thermodynamic geometry are comparatively discussed on the basis of the Lennard-Jones potential. The first two approaches approximate the high-density fluid state well when the repulsive interparticle interactions become dominant, which is typically the case close to the freezing line. However, previous studies of Rosenfeld-Tarazona scaling for the isochoric heat capacity and its relation to isomorph theory reveal deviations for the temperature dependence. It turns out that a definition of a state region in which repulsive interactions dominate is required for achieving consistent results. The Riemannian thermodynamic scalar curvature R allows for such a classification, indicating predominantly repulsive interactions by R>0. An analysis of the isomorphic character of the freezing line and the validity of Rosenfeld-Tarazona temperature scaling show that these approaches are consistent only in a small state region.
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Affiliation(s)
| | - Andreas Köster
- Thermodynamics and Energy Technology, University of Paderborn, 33098 Paderborn, Germany
| | - Jadran Vrabec
- Thermodynamics and Energy Technology, University of Paderborn, 33098 Paderborn, Germany
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26
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Mareev E, Aleshkevich V, Potemkin F, Bagratashvili V, Minaev N, Gordienko V. Anomalous behavior of nonlinear refractive indexes of CO 2 and Xe in supercritical states. OPTICS EXPRESS 2018; 26:13229-13238. [PMID: 29801350 DOI: 10.1364/oe.26.013229] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/09/2018] [Accepted: 04/03/2018] [Indexed: 06/08/2023]
Abstract
Direct measurement of pressure dependent nonlinear refractive index of CO2 and Xe in subcritical and supercritical states are reported. In the vicinity of the ridge (or the Widom line), corresponding to the maximum density fluctuations, the nonlinear refractive index reaches a maximum value (up to 4.8*10-20m2/W in CO2 and 3.5*10-20m2/W in Xe). Anomalous behavior of the nonlinear refractive index in the vicinity of a ridge is caused by the cluster formation. That corresponds to the results of our theoretical assumption based on the modified Langevin theory.
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27
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Pipich V, Schwahn D. Densification of Supercritical Carbon Dioxide Accompanied by Droplet Formation When Passing the Widom Line. PHYSICAL REVIEW LETTERS 2018; 120:145701. [PMID: 29694157 DOI: 10.1103/physrevlett.120.145701] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/20/2017] [Revised: 01/23/2018] [Indexed: 06/08/2023]
Abstract
Thermal density fluctuations of supercritical CO_{2} were explored using small-angle neutron scattering (SANS), whose amplitude (susceptibility) and correlation length show the expected maximum at the Widom line. At low pressure, the susceptibility is in excellent agreement with the evaluated values on the basis of mass density measurements. At about 20 bar beyond the Widom line, SANS shows the formation of droplets accompanied by an enhanced number density of the supercritical fluid. The corresponding borderline is interpreted as a Frenkel line separating gas- and liquidlike regimes.
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Affiliation(s)
- Vitaliy Pipich
- Forschungszentrum Jülich GmbH, Jülich Centre for Neutron Science (JCNS) at Heinz Maier-Leibnitz Zentrum (MLZ), Lichtenbergstraße 1, D-85748 Garching, Germany
| | - Dietmar Schwahn
- Technische Universität München, Forschungs-Neutronenquelle Heinz Maier-Leibnitz (FRM II), James-Franck-Straße 1, D-85748 Garching, Germany
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28
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Yoon TJ, Lee YW. Current theoretical opinions and perspectives on the fundamental description of supercritical fluids. J Supercrit Fluids 2018. [DOI: 10.1016/j.supflu.2017.11.022] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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29
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Pazmiño Betancourt BA, Starr FW, Douglas JF. String-like collective motion in the α- and β-relaxation of a coarse-grained polymer melt. J Chem Phys 2018; 148:104508. [DOI: 10.1063/1.5009442] [Citation(s) in RCA: 37] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Affiliation(s)
- Beatriz A. Pazmiño Betancourt
- Materials Science and Engineering Division, National Institute of Standards and Technology, Gaithersburg, Maryland 20899, USA
- Department of Physics, Wesleyan University, Middletown, Connecticut 06459, USA
| | - Francis W. Starr
- Department of Physics, Wesleyan University, Middletown, Connecticut 06459, USA
| | - Jack F. Douglas
- Materials Science and Engineering Division, National Institute of Standards and Technology, Gaithersburg, Maryland 20899, USA
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30
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Ghosh K, Krishnamurthy CV. Structural behavior of supercritical fluids under confinement. Phys Rev E 2018; 97:012131. [PMID: 29448330 DOI: 10.1103/physreve.97.012131] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2017] [Indexed: 11/07/2022]
Abstract
The existence of the Frenkel line in the supercritical regime of a Lennard-Jones (LJ) fluid shown through molecular dynamics (MD) simulations initially and later corroborated by experiments on argon opens up possibilities of understanding the structure and dynamics of supercritical fluids in general and of the Frenkel line in particular. The location of the Frenkel line, which demarcates two distinct physical states, liquidlike and gaslike within the supercritical regime, has been established through MD simulations of the velocity autocorrelation (VACF) and radial distribution function (RDF). We, in this article, explore the changes in the structural features of supercritical LJ fluid under partial confinement using atomistic walls. The study is carried out across the Frenkel line through a series of MD simulations considering a set of thermodynamics states in the supercritical regime (P=5000 bar, 240K≤T≤1500K) of argon well above the critical point. Confinement is partial, with atomistic walls located normal to z and extending to "infinity" along the x and y directions. In the "liquidlike" regime of the supercritical phase, particles are found to be distributed in distinct layers along the z axis with layer spacing less than one atomic diameter and the lateral RDF showing amorphous-like structure for specific spacings (packing frustration) and non-amorphous-like structure for other spacings. Increasing the rigidity of the atomistic walls is found to lead to stronger layering and increased structural order. For confinement with reflective walls, layers are found to form with one atomic diameter spacing and the lateral RDF showing close-packed structure for the smaller confinements. Translational order parameter and excess entropy assessment confirms the ordering taking place for atomistic wall and reflective wall confinements. In the "gaslike" regime of the supercritical phase, particle distribution along the spacing and the lateral RDF exhibit features not significantly different from that due to normal gas regime. The heterogeneity across the Frenkel line, found to be present both in bulk and confined systems, might cause the breakdown of the universal scaling between structure and dynamics of fluids necessitating the determination of a unique relationship between them.
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Affiliation(s)
- Kanka Ghosh
- Department of Physics, Indian Institute of Technology Madras, Chennai 600036, India
| | - C V Krishnamurthy
- Department of Physics, Indian Institute of Technology Madras, Chennai 600036, India
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31
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Raman AS, Li H, Chiew YC. Widom line, dynamical crossover, and percolation transition of supercritical oxygen via molecular dynamics simulations. J Chem Phys 2018; 148:014502. [PMID: 29306275 DOI: 10.1063/1.5002699] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023] Open
Abstract
Supercritical oxygen, a cryogenic fluid, is widely used as an oxidizer in jet propulsion systems and is therefore of paramount importance in gaining physical insights into processes such as transcritical and supercritical vaporization. It is well established in the scientific literature that the supercritical state is not homogeneous but, in fact, can be demarcated into regions with liquid-like and vapor-like properties, separated by the "Widom line." In this study, we identified the Widom line for oxygen, constituted by the loci of the extrema of thermodynamic response functions (heat capacity, volumetric thermal expansion coefficient, and isothermal compressibility) in the supercritical region, via atomistic molecular dynamics simulations. We found that the Widom lines derived from these response functions all coincide near the critical point until about 25 bars and 15-20 K, beyond which the isothermal compressibility line begins to deviate. We also obtained the crossover from liquid-like to vapor-like behavior of the translational diffusion coefficient, shear viscosity, and rotational relaxation time of supercritical oxygen. While the crossover of the translational diffusion coefficient and shear viscosity coincided with the Widom lines, the rotational relaxation time showed a crossover that was largely independent of the Widom line. Further, we characterized the clustering behavior and percolation transition of supercritical oxygen molecules, identified the percolation threshold based on the fractal dimension of the largest cluster and the probability of finding a cluster that spans the system in all three dimensions, and found that the locus of the percolation threshold also coincided with the isothermal compressibility Widom line. It is therefore clear that supercritical oxygen is far more complex than originally perceived and that the Widom line, dynamical crossovers, and percolation transitions serve as useful routes to better our understanding of the supercritical state.
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Affiliation(s)
- Abhinav S Raman
- Department of Chemical and Biochemical Engineering, Rutgers University, Piscataway, New Jersey 08854, USA
| | - Huiyong Li
- Department of Chemical and Biochemical Engineering, Rutgers University, Piscataway, New Jersey 08854, USA
| | - Y C Chiew
- Department of Chemical and Biochemical Engineering, Rutgers University, Piscataway, New Jersey 08854, USA
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32
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Smith D, Hakeem MA, Parisiades P, Maynard-Casely HE, Foster D, Eden D, Bull DJ, Marshall ARL, Adawi AM, Howie R, Sapelkin A, Brazhkin VV, Proctor JE. Crossover between liquidlike and gaslike behavior in CH_{4} at 400 K. Phys Rev E 2017; 96:052113. [PMID: 29347717 DOI: 10.1103/physreve.96.052113] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2017] [Indexed: 06/07/2023]
Abstract
We report experimental evidence for a crossover between a liquidlike state and a gaslike state in fluid methane (CH_{4}). This crossover is observed in all of our experiments, up to a temperature of 397 K, 2.1 times the critical temperature of methane. The crossover has been characterized with both Raman spectroscopy and x-ray diffraction in a number of separate experiments, and confirmed to be reversible. We associate this crossover with the Frenkel line-a recently hypothesized crossover in dynamic properties of fluids extending to arbitrarily high pressure and temperature, dividing the phase diagram into separate regions where the fluid possesses liquidlike and gaslike properties. On the liquidlike side the Raman-active vibration increases in frequency linearly as pressure is increased, as expected due to the repulsive interaction between adjacent molecules. On the gaslike side this competes with the attractive van der Waals potential leading the vibration frequency to decrease as pressure is increased.
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Affiliation(s)
- D Smith
- Materials and Physics Research Group, School of Computing, Science and Engineering, University of Salford, Manchester M5 4WT, United Kingdom
- School of Mathematics and Physical Sciences, University of Hull, Hull HU6 7RX, United Kingdom
| | - M A Hakeem
- Materials and Physics Research Group, School of Computing, Science and Engineering, University of Salford, Manchester M5 4WT, United Kingdom
| | - P Parisiades
- European Synchrotron Radiation Facility, Beamline ID27, Boîte Postale 220, Grenoble, France
- IMPMC, Université Pierre et Marie Curie, 4 place Jussieu, 75005 Paris, France
| | - H E Maynard-Casely
- Australian Nuclear Science and Technology Organisation, Locked Bag 2001, Kirrawee DC, New South Wales, 2232, Australia
| | - D Foster
- Materials and Physics Research Group, School of Computing, Science and Engineering, University of Salford, Manchester M5 4WT, United Kingdom
| | - D Eden
- Materials and Physics Research Group, School of Computing, Science and Engineering, University of Salford, Manchester M5 4WT, United Kingdom
| | - D J Bull
- Materials and Physics Research Group, School of Computing, Science and Engineering, University of Salford, Manchester M5 4WT, United Kingdom
| | - A R L Marshall
- School of Mathematics and Physical Sciences, University of Hull, Hull HU6 7RX, United Kingdom
| | - A M Adawi
- School of Mathematics and Physical Sciences, University of Hull, Hull HU6 7RX, United Kingdom
| | - R Howie
- SUPA, School of Physics and Centre for Science at Extreme Conditions, University of Edinburgh, Edinburgh EH9 3JZ, United Kingdom
- Center for High Pressure Science & Technology Advanced Research (HPSTAR), Shanghai 201203, People's Republic of China
| | - A Sapelkin
- School of Physics and Astronomy, Queen Mary University of London, London E1 4NS, United Kingdom
| | - V V Brazhkin
- Institute for High Pressure Physics, RAS, 108440 Troitsk, Moscow, Russia
| | - J E Proctor
- Materials and Physics Research Group, School of Computing, Science and Engineering, University of Salford, Manchester M5 4WT, United Kingdom
- School of Mathematics and Physical Sciences, University of Hull, Hull HU6 7RX, United Kingdom
- Photon Science Institute and School of Electrical and Electronic Engineering, The University of Manchester, Oxford Road, Manchester M13 9PL, United Kingdom
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33
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Aitken F, Volino F, Mendoza-Luna LG, Haeften KV, Eloranta J. A thermodynamic model to predict electron mobility in superfluid helium. Phys Chem Chem Phys 2017; 19:15821-15832. [PMID: 28585629 DOI: 10.1039/c7cp03067c] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Electron mobility in superfluid helium is modeled between 0.1 and 2.2 K by a van der Waals-type thermodynamic equation of state, which relates the free volume of solvated electrons to temperature, density, and phase dependent internal pressure. The model is first calibrated against known electron mobility reference data along the saturated vapor pressure line and then validated to reproduce the existing mobility literature values as a function of pressure and temperature with at least 10% accuracy. Four different electron mobility regimes are identified: (1) Landau critical velocity limit (T ≈ 0), (2) mobility limited by thermal phonons (T < 0.6 K), (3) thermal phonon and discrete roton scattering ("roton gas") limited mobility (0.6 K < T < 1.2 K), and (4) the viscous liquid ("roton continuum") limit (T > 1.2 K) where the ion solvation structure directly determines the mobility. In the latter regime, the Stokes equation can be used to estimate the hydrodynamic radius of the solvated electron based on its mobility and fluid viscosity. To account for the non-continuum behavior appearing below 1.2 K, the temperature and density dependent Millikan-Cunningham factor is introduced. The hydrodynamic electron bubble radii predicted by the present model appear generally larger than the solvation cavity interface barycenter values obtained from density functional theory (DFT) calculations. Based on the classical Stokes law, this difference can arise from the variation of viscosity and flow characteristics around the electron. The calculated DFT liquid density profiles show distinct oscillations at the vacuum/liquid interface, which increase the interface rigidity.
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Affiliation(s)
- Frédéric Aitken
- Univ. Grenoble Alpes, CNRS, Grenoble INP, G2ELab, F-38000 Grenoble, France.
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34
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Ruppeiner G, Dyjack N, McAloon A, Stoops J. Solid-like features in dense vapors near the fluid critical point. J Chem Phys 2017; 146:224501. [DOI: 10.1063/1.4984915] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Affiliation(s)
- George Ruppeiner
- Division of Natural Sciences, New College of Florida, 5800 Bay Shore Road, Sarasota, Florida 34243, USA
| | - Nathan Dyjack
- Center for Genes, Environment & Health, National Jewish Health, 1400 S Jackson St., Denver, Colorado 80206, USA
| | - Abigail McAloon
- Oak Hill School, 86397 Eldon Schafer Dr, Eugene, Oregon 97405, USA
| | - Jerry Stoops
- Division of Natural Sciences, New College of Florida, 5800 Bay Shore Road, Sarasota, Florida 34243, USA
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35
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Bellissima S, Neumann M, Guarini E, Bafile U, Barocchi F. Density of states and dynamical crossover in a dense fluid revealed by exponential mode analysis of the velocity autocorrelation function. Phys Rev E 2017; 95:012108. [PMID: 28208443 DOI: 10.1103/physreve.95.012108] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2016] [Indexed: 11/07/2022]
Abstract
Extending a preceding study of the velocity autocorrelation function (VAF) in a simulated Lennard-Jones fluid [Phys. Rev. E 92, 042166 (2015)PLEEE81539-375510.1103/PhysRevE.92.042166] to cover higher-density and lower-temperature states, we show that the recently demonstrated multiexponential expansion method allows for a full account and understanding of the basic dynamical processes encompassed by a fundamental quantity as the VAF. In particular, besides obtaining evidence of a persisting long-time tail, we assign specific and unambiguous physical meanings to groups of exponential modes related to the longitudinal and transverse collective dynamics, respectively. We have made this possible by consistently introducing the interpretation of the VAF frequency spectrum as a global density of states in fluids, generalizing a solid-state concept, and by giving to specific spectral components, obtained through the VAF exponential expansion, the corresponding meaning of partial densities of states relative to specific dynamical processes. The clear identification of a high-frequency oscillation of the VAF with the near-top excitation frequency in the dispersion curve of acoustic waves is a neat example of the power of the method. As for the transverse mode contribution, its analysis turns out to be particularly important, because the multiexponential expansion reveals a transition marking the onset of propagating excitations when the density is increased beyond a threshold value. While this finding agrees with the recent literature debating the issue of dynamical crossover boundaries, such as the one identified with the Frenkel line, we can add detailed information on the modes involved in this specific process in the domains of both time and frequency. This will help obtain a still missing full account of transverse dynamics, in both its nonpropagating and propagating aspects which are linked through dynamical transitions depending on both the thermodynamic states and the excitation wave vectors.
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Affiliation(s)
- S Bellissima
- Dipartimento di Fisica e Astronomia, Università degli Studi di Firenze, via G. Sansone 1, I-50019 Sesto Fiorentino, Italy
| | - M Neumann
- Fakultät für Physik der Universität Wien, Strudlhofgasse 4, A-1090 Wien, Austria
| | - E Guarini
- Dipartimento di Fisica e Astronomia, Università degli Studi di Firenze, via G. Sansone 1, I-50019 Sesto Fiorentino, Italy
| | - U Bafile
- Consiglio Nazionale delle Ricerche, Istituto dei Sistemi Complessi, via Madonna del Piano 10, I-50019 Sesto Fiorentino, Italy
| | - F Barocchi
- Dipartimento di Fisica e Astronomia, Università degli Studi di Firenze, via G. Sansone 1, I-50019 Sesto Fiorentino, Italy
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Bolmatov D, Zhernenkov M, Zav'yalov D, Stoupin S, Cunsolo A, Cai YQ. Thermally triggered phononic gaps in liquids at THz scale. Sci Rep 2016; 6:19469. [PMID: 26763899 PMCID: PMC4725891 DOI: 10.1038/srep19469] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2015] [Accepted: 11/27/2015] [Indexed: 12/22/2022] Open
Abstract
In this paper we present inelastic X-ray scattering experiments in a diamond anvil cell and molecular dynamic simulations to investigate the behavior of phononic excitations in liquid Ar. The spectra calculated using molecular dynamics were found to be in a good agreement with the experimental data. Furthermore, we observe that, upon temperature increases, a low-frequency transverse phononic gap emerges while high-frequency propagating modes become evanescent at the THz scale. The effect of strong localization of a longitudinal phononic mode in the supercritical phase is observed for the first time. The evidence for the high-frequency transverse phononic gap due to the transition from an oscillatory to a ballistic dynamic regimes of motion is presented and supported by molecular dynamics simulations. This transition takes place across the Frenkel line thermodynamic limit which demarcates compressed liquid and non-compressed fluid domains on the phase diagram and is supported by calculations within the Green-Kubo phenomenological formalism. These results are crucial to advance the development of novel terahertz thermal devices, phononic lenses, mirrors, and other THz metamaterials.
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Affiliation(s)
- Dima Bolmatov
- National Synchrotron Light Source II, Brookhaven National Laboratory, Upton, NY 11973, USA
| | - Mikhail Zhernenkov
- National Synchrotron Light Source II, Brookhaven National Laboratory, Upton, NY 11973, USA
| | | | - Stanislav Stoupin
- Advanced Photon Source, Argonne National Laboratory, Argonne, Illinois 60439, USA
| | - Alessandro Cunsolo
- National Synchrotron Light Source II, Brookhaven National Laboratory, Upton, NY 11973, USA
| | - Yong Q Cai
- National Synchrotron Light Source II, Brookhaven National Laboratory, Upton, NY 11973, USA
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