1
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Skarmoutsos I. Substantial breakdown of the hydrogen-bonding network, local density inhomogeneities and fluid-liquid structural transitions in supercritical octanol-1: A molecular dynamics investigation. J Chem Phys 2024; 161:044506. [PMID: 39056384 DOI: 10.1063/5.0219417] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2024] [Accepted: 07/11/2024] [Indexed: 07/28/2024] Open
Abstract
Molecular dynamics simulations have been employed to explore the hydrogen-bonding structure and dynamics in supercritical octanol-1 at a near-critical temperature and up to high densities and pressures. A substantial breakdown of the hydrogen-bonding network when going from ambient-liquid to supercritical conditions is revealed. The fraction of the non-hydrogen bonded molecules significantly increases in supercritical octanol-1, and a substantial decrease in the intermittent hydrogen-bond lifetime is observed. This behavior is also reflected on the maximum local density augmentation, which is comparable to the values obtained for non-polar and non-hydrogen bonded fluids. The existence of a structural transition from an inhomogeneous fluid phase to a soft-liquid one at densities higher than 2.0 ρc is also revealed. At higher densities, a significant change in the reorientational relaxation process is observed, reflected on the significant increase in the ratio of the Legendre reorientational times τ1R/τ2R. The latter becomes much higher than the value predicted by the Debye model of diffusive reorientation and the corresponding ratio for ambient liquid octanol-1. The non-polar tail of octanol-1 under supercritical conditions reorients more slowly in comparison with the polar tail. Interestingly, the opposite behavior is observed for the ambient liquid, further verifying the strong effect of the breakdown of the hydrogen bonding network on the properties of supercritical octanol-1. In accordance with the above-mentioned findings, the static dielectric constant of supercritical octanol-1 is very low even at high densities and pressures, comparable to the values obtained for non-polar and non-hydrogen bonded fluids.
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Affiliation(s)
- Ioannis Skarmoutsos
- Laboratory of Physical Chemistry, Department of Chemistry, University of Ioannina, 45110 Ioannina, Greece
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2
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Hwang W, Kwon S, Lee WB, Kim Y. Self-assembly prediction of architecture-controlled bottlebrush copolymers in solution using graph convolutional networks. SOFT MATTER 2024; 20:4905-4915. [PMID: 38867573 DOI: 10.1039/d4sm00453a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/14/2024]
Abstract
The investigation of bottlebrush copolymer self-assembly in solution involves a comprehensive approach integrating simulation and experimental research, due to their unique physical characteristics. However, the intricate architecture of bottlebrush copolymers and the diverse solvent conditions introduce a wide range of parameter spaces. In this study, we investigated the solution self-assembly behavior of bottlebrush copolymers by combining dissipative particle dynamics (DPD) simulation results and machine learning (ML) including graph convolutional networks (GCNs). The architecture of bottlebrush copolymers is encoded by graphs including connectivity, side chain length, bead types, and interaction parameters of DPD simulation. Using GCN, we accurately predicted the single chain properties of bottlebrush copolymers with over 95% accuracy. Furthermore, phase behavior was precisely predicted using these single chain properties. Shapley additive explanations (SHAP) values of single chain properties to the various self-assembly morphologies were calculated to investigate the correlation between single chain properties and morphologies. In addition, we analyzed single chain properties and phase behavior as a function of DPD interaction parameters, extracting relevant physical properties for vesicle morphology formation. This work paves the way for tailored design in solution of self-assembled nanostructures of bottlebrush copolymers, offering a GCN framework for precise prediction of self-assembly morphologies under various chain architectures and solvent conditions.
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Affiliation(s)
- Wooseop Hwang
- Department of Materials Science and Engineering, Korea University, Seoul 02841, Republic of Korea.
| | - Sangwoo Kwon
- 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.
| | - YongJoo Kim
- Department of Materials Science and Engineering, Korea University, Seoul 02841, Republic of Korea.
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3
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Dong M, Xu J, Wang Y. Critical Threshold for Bubble-like Nucleation during Pseudoboiling at Supercritical Pressures. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2024; 40:13276-13291. [PMID: 38861685 DOI: 10.1021/acs.langmuir.4c01477] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2024]
Abstract
Supercritical pseudoboiling was proposed in the 1950s-1960s. Recently, evaporation-like and boiling-like heat transfer have been directly observed in macroscopic scales, and the contribution of pseudoboiling to the total heat transfer rate has been quantitatively characterized experimentally. Here, we explore the critical threshold to generate a bubble-like nucleus at supercritical pressure at the atomic scale, characterized by the total energy (Te = Ke + Pe, where Ke and Pe are kinetic energy and potential energy, respectively). Molecular dynamics simulations are performed, including an argon fluid box heated by a solid wall having its temperature above the fluid temperature. The fluid pressure is controlled by a movable piston wall opposite the heating wall. The effects of pressure, nonuniform heating, and surface wettability on pseudoboiling are investigated. It is found that the criterion Te > 0 should be satisfied for subcritical boiling, matching that reported previously. The criterion for supercritical pseudoboiling was newly obtained such that Te > 0.012 eV at 8 MPa for argon, but the threshold increases as pressure increases. Nonuniform heating and surface wettability do not affect the critical threshold of Te for bubble-like nucleation but affect the location of the initially generated bubble-like nucleus and the stabilized pseudofilm or pseudonucleate heat transfer modes, where the former is similar to (vapor) film boiling and the latter is similar to nucleate boiling at subcritical pressure. Because pseudoboiling occurs without surface tension at supercritical pressure, we observe that the bubble-like structure may not display a perfectly smooth gas-liquid interface but may display an irregular pattern instead. Our work explains pseudoboiling from the viewpoint of the competition between kinetic energy and potential energy and presents a link regarding boiling in the two domains of subcritical pressure and supercritical pressure.
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Affiliation(s)
- Ming Dong
- Beijing Key Laboratory of Multiphase Flow and Heat Transfer for Low Grade Energy Utilization, North China Electric Power University, Beijing 102206, China
| | - 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 Huairou Laboratory, Beijing 101400, China
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4
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Ranieri U, Formisano F, Gorelli FA, Santoro M, Koza MM, De Francesco A, Bove LE. Crossover from gas-like to liquid-like molecular diffusion in a simple supercritical fluid. Nat Commun 2024; 15:4142. [PMID: 38755136 PMCID: PMC11099187 DOI: 10.1038/s41467-024-47961-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2023] [Accepted: 04/15/2024] [Indexed: 05/18/2024] Open
Abstract
According to textbooks, no physical observable can be discerned allowing to distinguish a liquid from a gas beyond the critical point. Yet, several proposals have been put forward challenging this view and various transition boundaries between a gas-like and a liquid-like behaviour, including the so-called Widom and Frenkel lines, and percolation line, have been suggested to delineate the supercritical state space. Here we report observation of a crossover from gas-like (Gaussian) to liquid-like (Lorentzian) self-dynamic structure factor by incoherent quasi-elastic neutron scattering measurements on supercritical fluid methane as a function of pressure, along the 200 K isotherm. The molecular self-diffusion coefficient was derived from the best Gaussian (at low pressures) or Lorentzian (at high pressures) fits to the neutron spectra. The Gaussian-to-Lorentzian crossover is progressive and takes place at about the Widom line intercept (59 bar). At considerably higher pressures, a liquid-like jump diffusion mechanism properly describes the supercritical fluid on both sides of the Frenkel line. The present observation of a gas-like to liquid-like crossover in the self dynamics of a simple supercritical fluid confirms emerging views on the unexpectedly complex physics of the supercritical state, and could have planet-wide implications and possible industrial applications in green chemistry.
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Affiliation(s)
- Umbertoluca Ranieri
- Dipartimento di Fisica, Università di Roma La Sapienza, Piazzale Aldo Moro 5, Roma, 00187, Italy
- Centre for Science at Extreme Conditions and School of Physics and Astronomy, University of Edinburgh, Edinburgh, EH9 3FD, UK
| | - Ferdinando Formisano
- CNR - Istituto Officina dei Materiali (IOM), Grenoble, INSIDE@ILL, 71 Avenue des Martyrs, Grenoble, Cedex 9, France.
- Institut Laue-Langevin, 71 Avenue des Martyrs, Grenoble, Cedex 9, France.
| | - Federico A Gorelli
- Center for High Pressure Science and Technology Advanced Research (HPSTAR), 1690 Cailun Road, Shanghai, 201203, China.
- Shanghai Advanced Research in Physical Sciences (SHARPS), Pudong, Shanghai, 201203, China.
- Consiglio Nazionale delle Ricerche, Istituto Nazionale di Ottica, CNR-INO, Via Nello Carrara 1, Sesto Fiorentino (FI), 50019, Italy.
| | - Mario Santoro
- Consiglio Nazionale delle Ricerche, Istituto Nazionale di Ottica, CNR-INO, Via Nello Carrara 1, Sesto Fiorentino (FI), 50019, Italy
- European Laboratory for Nonlinear Spectroscopy, LENS, Via Nello Carrara 1, Sesto Fiorentino (FI), 50019, Italy
| | - Michael Marek Koza
- Institut Laue-Langevin, 71 Avenue des Martyrs, Grenoble, Cedex 9, France
| | - Alessio De Francesco
- CNR - Istituto Officina dei Materiali (IOM), Grenoble, INSIDE@ILL, 71 Avenue des Martyrs, Grenoble, Cedex 9, France
- Institut Laue-Langevin, 71 Avenue des Martyrs, Grenoble, Cedex 9, France
| | - Livia E Bove
- Dipartimento di Fisica, Università di Roma La Sapienza, Piazzale Aldo Moro 5, Roma, 00187, Italy
- Laboratory of Quantum Magnetism, Institute of Physics, École Polytechnique Fédérale de Lausanne, Lausanne, CH-1015, Switzerland
- Institut de Minéralogie, de Physique des Matériaux et de Cosmochimie, Sorbonne Université, UMR CNRS 7590, 5 Place Jussieu, Paris, 75005, France
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5
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Lundin AA, Chaikina YA, Shushin AI, Umanskii SY. On the Capabilities of Optical Diagnostics Methods to Monitor the State of Supercritical Fluids near the Widom Line. RUSSIAN JOURNAL OF PHYSICAL CHEMISTRY B 2022. [DOI: 10.1134/s1990793122080115] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
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6
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López-Picón J, Escamilla-Herrera L, Torres-Arenas J. The square-well fluid: A thermodynamic geometric view. J Mol Liq 2022. [DOI: 10.1016/j.molliq.2022.120607] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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7
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Wang Y, Liu G. Inhomogeneity Effects on Reactions in Supercritical Fluids: A Computational Study on the Pyrolysis of n-Decane. JACS AU 2022; 2:2081-2088. [PMID: 36186566 PMCID: PMC9516705 DOI: 10.1021/jacsau.2c00359] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/19/2022] [Revised: 08/24/2022] [Accepted: 08/24/2022] [Indexed: 06/16/2023]
Abstract
Supercritical fluids exhibit peculiar inhomogeneity, which strongly affects reaction behaviors in them. However, explanations for inhomogeneity and its effect on reactions are both ambiguous so far. Here, we provide an atomic-level understanding of inhomogeneity effects on reactions via the computational method, with the example of n-decane pyrolysis under supercritical conditions. We describe the characteristic pyrolysis behaviors through collective variable-driven hyperdynamics (CVHD) simulations and explain the inhomogeneity of supercritical n-decane as the coexistence of gas-like and liquid-like atoms by a trained machine learning classifier. Due to their specific local environment, the appearance of liquid-like atoms under supercritical conditions significantly increases the type and frequency of bimolecular reactions and eventually causes changes in product distributions. Future research with this method is expected to extend the effect of inhomogeneity on other reactions under supercritical conditions or other condensed phases.
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Affiliation(s)
- Yutong Wang
- Key
Laboratory for Green Chemical Technology of Ministry of Education,
School of Chemical Engineering and Technology, Tianjin University, Tianjin 300072, China
| | - Guozhu Liu
- Key
Laboratory for Green Chemical Technology of Ministry of Education,
School of Chemical Engineering and Technology, Tianjin University, Tianjin 300072, China
- Haihe
Laboratory of Sustainable Chemical Transformations, Tianjin 300192, China
- Zhejiang
Institute of Tianjin University, Ningbo, Zhejiang 315201, China
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8
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Vestrick S, Fischer C, Khoukaz A. Crossing the Widom line: Cluster formation as sensitive probe of supercritical fluids. J Supercrit Fluids 2022. [DOI: 10.1016/j.supflu.2022.105686] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
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9
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Skarmoutsos I, Samios J, Guardia E. Fingerprints of the Crossing of the Frenkel and Melting Line on the Properties of High-Pressure Supercritical Water. J Phys Chem Lett 2022; 13:7636-7644. [PMID: 35952379 DOI: 10.1021/acs.jpclett.2c01477] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
Using molecular dynamics simulations in combination with the two-phase thermodynamic model, we reveal novel characteristic fingerprints of the crossing of the Frenkel and melting line on the properties of high-pressure water at a near-critical temperature (1.03Tc). The crossing of the Frenkel line at about 1.17 GPa is characterized by a crossover in the rotational and translational entropy ratio Srot/Strans, indicating a change in the coupling between translational and rotational motions which is also reflected in the shape of the rotational density of states. The observed isosbestic points in the translational and rotational density of states are also blue-shifted at density and pressure conditions higher than the ones corresponding to the Frenkel line. The first-order phase transition from a rigid liquid to a face-centered cubic plastic crystal phase at about 8.5 GPa is reflected in the discontinuous changes in the translational and rotational entropy, particularly in the significant increase of the ratio Srot/Strans. A noticeable discontinuous increase of the dielectric constant has also been revealed when crossing this melting line, which is attributed to the different arrangement of the water molecules in the plastic crystal phase. The reorientational dynamics in the plastic crystal phase is faster in comparison with the "rigid" liquid-like phase, but it remains unchanged upon a further pressure increase in the range of 8.5-11 GPa.
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Affiliation(s)
- Ioannis Skarmoutsos
- Laboratory of Physical Chemistry, Department of Chemistry, University of Ioannina, 45110 Ioannina, Greece
| | - Jannis Samios
- Department of Chemistry, Laboratory of Physical Chemistry, National and Kapodistrian University of Athens, Panepistimiopolis 157-71, Athens, Greece
| | - Elvira Guardia
- Departament de Física, Universitat Politècnica de Catalunya, Campus Nord-Edifici B4-B5, Jordi Girona 1-3, Barcelona E-08034, Spain
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10
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Widom line of supercritical CO2 calculated by equations of state and molecular dynamics simulation. J CO2 UTIL 2022. [DOI: 10.1016/j.jcou.2022.102075] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
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11
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Liu M, Tang J, Liu S, Xi D, Min L, Zang J, Liu G, Wang J, Huang S, Huang Y. Modified Landau model for fluids: A rethink of pseudoboiling theory for supercritical fluids. J Supercrit Fluids 2022. [DOI: 10.1016/j.supflu.2022.105554] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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12
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Zanetti-Polzi L, Daidone I, Amadei A. A general statistical mechanical model for fluid system thermodynamics: Application to sub- and super-critical water. J Chem Phys 2022; 156:044506. [DOI: 10.1063/5.0079206] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Affiliation(s)
- Laura Zanetti-Polzi
- Center S3, CNR-Institute of Nanoscience, Via Campi 213/A, 41125 Modena, Italy
| | - Isabella Daidone
- Department of Physical and Chemical Sciences, University of L’Aquila, via Vetoio (Coppito 1), 67010 L’Aquila, Italy
| | - Andrea Amadei
- Department of Chemical and Technological Sciences, University of Rome “Tor Vergata”, Via della Ricerca Scientifica, I-00185 Rome, Italy
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13
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Sun P, Hastings JB, Ishikawa D, Baron AQR, Monaco G. Universal Two-Component Dynamics in Supercritical Fluids. J Phys Chem B 2021; 125:13494-13501. [PMID: 34855409 PMCID: PMC8686117 DOI: 10.1021/acs.jpcb.1c07900] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/02/2022]
Abstract
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Despite the technological importance of supercritical fluids, controversy remains
about the details of their microscopic dynamics. In this work, we
study four supercritical fluid systems—water, Si, Te, and Lennard-Jones
fluid—via classical molecular dynamics simulations. A universal
two-component behavior is observed in the intermolecular dynamics
of these systems, and the changing ratio between the two components
leads to a crossover from liquidlike to gaslike dynamics, most rapidly
around the Widom line. We find evidence to connect the liquidlike
component dominating at lower temperatures with intermolecular bonding
and the component prominent at higher temperatures with free-particle,
gaslike dynamics. The ratio between the components can be used to
describe important properties of the fluid, such as its self-diffusion
coefficient, in the transition region. Our results provide an insight
into the fundamental mechanism controlling the dynamics of supercritical
fluids and highlight the role of spatiotemporally inhomogeneous dynamics
even in thermodynamic states where no large-scale fluctuations exist
in the fluid.
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Affiliation(s)
- Peihao Sun
- SLAC National Accelerator Laboratory, 2575 Sand Hill Road, Menlo Park, California 94025, United States.,Physics Department, Stanford University, 382 Via Pueblo Mall, Stanford, California 94305, United States
| | - J B Hastings
- SLAC National Accelerator Laboratory, 2575 Sand Hill Road, Menlo Park, California 94025, United States
| | - Daisuke Ishikawa
- Materials Dynamics Laboratory, RIKEN SPring-8 Center, 1-1-1 Kouto, Sayo, Hyogo 679-5148, Japan
| | - Alfred Q R Baron
- Materials Dynamics Laboratory, RIKEN SPring-8 Center, 1-1-1 Kouto, Sayo, Hyogo 679-5148, Japan
| | - Giulio Monaco
- Dipartimento di Fisica e Astronomia, Università di Padova, 35131 Padova, Italy
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14
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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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15
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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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16
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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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17
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Pruteanu CG, Proctor JE, Alderman OLG, Loveday JS. Structural Markers of the Frenkel Line in the Proximity of Widom Lines. J Phys Chem B 2021; 125:8902-8906. [PMID: 34324365 DOI: 10.1021/acs.jpcb.1c04690] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
We have performed a neutron scattering experiment on supercritical fluid nitrogen at 160 K (1.27 TC) over a wide pressure range (7.8 MPa/0.260 g/mL-125 MPa/0.805 g/mL). This has enabled us to study the process by which nitrogen changes from a fluid that exhibits gaslike behavior to one that exhibits rigid liquidlike behavior at a temperature close to, but above, the critical temperature by crossing the Widom lines followed by the Frenkel line on pressure (density) increase. We find that the Frenkel line transition is indicated by a transition to a regime of rigid liquidlike behavior in which the coordination number remains constant within error, in agreement with our previous work at 300 K. The Frenkel line transition takes place at approximately the same density at 160 and 300 K. The data do not conclusively show an additional transition at the location of the known Widom lines. We find that behavior remains gaslike until the Frenkel line is crossed and our data support the hypothesis that Widom line transitions are density increase-driven.
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Affiliation(s)
- Ciprian G Pruteanu
- Department of Earth Sciences, University College London, Gower Street, London WC1E 6BT, United Kingdom.,SUPA, School of Physics and Astronomy and Centre for Science at Extreme Conditions, The University of Edinburgh, Edinburgh EH9 3JZ, United Kingdom
| | - John E Proctor
- Materials and Physics Research Group, Newton Building, University of Salford, Manchester M5 4WT, United Kingdom
| | - Oliver L G Alderman
- ISIS Neutron and Muon Source, Rutherford Appleton Laboratory, Chilton, Didcot, Oxon OX11 0QX, United Kingdom
| | - John S Loveday
- 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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18
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Dulaney AR, Brady JF. Machine learning for phase behavior in active matter systems. SOFT MATTER 2021; 17:6808-6816. [PMID: 34223598 DOI: 10.1039/d1sm00266j] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
We demonstrate that deep learning techniques can be used to predict motility-induced phase separation (MIPS) in suspensions of active Brownian particles (ABPs) by creating a notion of phase at the particle level. Using a fully connected network in conjunction with a graph neural network we use individual particle features to predict to which phase a particle belongs. From this, we are able to compute the fraction of dilute particles to determine if the system is in the homogeneous dilute, dense, or coexistence region. Our predictions are compared against the MIPS binodal computed from simulation. The strong agreement between the two suggests that machine learning provides an effective way to determine the phase behavior of ABPs and could prove useful for determining more complex phase diagrams.
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Affiliation(s)
- Austin R Dulaney
- Division of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena, CA 91125, USA.
| | - John F Brady
- Division of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena, CA 91125, USA.
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19
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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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20
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21
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Mareev E, Semenov T, Lazarev A, Minaev N, Sviridov A, Potemkin F, Gordienko V. Optical Diagnostics of Supercritical CO 2 and CO 2-Ethanol Mixture in the Widom Delta. Molecules 2020; 25:molecules25225424. [PMID: 33228172 PMCID: PMC7699601 DOI: 10.3390/molecules25225424] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2020] [Revised: 11/16/2020] [Accepted: 11/17/2020] [Indexed: 11/16/2022] Open
Abstract
The supercritical CO2 (scCO2) is widely used as solvent and transport media in different technologies. The technological aspects of scCO2 fluid applications strongly depend on spatial–temporal fluctuations of its thermodynamic parameters. The region of these parameters’ maximal fluctuations on the p-T (pressure-temperature) diagram is called Widom delta. It has significant practical and fundamental interest. We offer an approach that combines optical measurements and molecular dynamics simulation in a wide range of pressures and temperatures. We studied the microstructure of supercritical CO2 fluid and its binary mixture with ethanol in a wide range of temperatures and pressures using molecular dynamics (MD) simulation. MD is used to retrieve a set of optical characteristics such as Raman spectra, refractive indexes and molecular refraction and was verified by appropriate experimental measurements. We demonstrated that in the Widom delta the monotonic dependence of the optical properties on the CO2 density is violated. It is caused by the rapid increase of density fluctuations and medium-sized (20–30 molecules) cluster formation. We identified the correlation between cluster parameters and optical properties of the media; in particular, it is established that the clusters in the Widom delta acts as a seed for clustering in molecular jets. MD demonstrates that the cluster formation is stronger in the supercritical CO2-ethanol mixture, where the extended binary clusters are formed; that is, the nonlinear refractive index significantly increased. The influence of the supercritical state in the cell on the formation of supersonic cluster jets is studied using the Mie scattering technique.
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Affiliation(s)
- Evgenii Mareev
- Institute of Photon Technologies of Federal Scientific Research Centre “Crystallography and Photonics” of Russian Academy of Sciences, Pionerskaya 2, Troitsk, 108840 Moscow, Russia; (N.M.); (A.S.); (V.G.)
- Faculty of Physics, M. V. Lomonosov Moscow State University, Leninskie Gory bld.1/2, 119991 Moscow, Russia; (T.S.); (F.P.)
- Correspondence:
| | - Timur Semenov
- Faculty of Physics, M. V. Lomonosov Moscow State University, Leninskie Gory bld.1/2, 119991 Moscow, Russia; (T.S.); (F.P.)
- Institute on Laser and Information Technologies—Branch of the Federal Scientific Research Centre “Crystallography and Photonics” of Russian Academy of Sciences, Svyatoozerskaya 1, Shatura, 140700 Moscow, Russia
| | - Alexander Lazarev
- Faculty of Chemistry, M. V. Lomonosov Moscow State University, Leninskie Gory bld.1/2, 119991 Moscow, Russia;
| | - Nikita Minaev
- Institute of Photon Technologies of Federal Scientific Research Centre “Crystallography and Photonics” of Russian Academy of Sciences, Pionerskaya 2, Troitsk, 108840 Moscow, Russia; (N.M.); (A.S.); (V.G.)
| | - Alexander Sviridov
- Institute of Photon Technologies of Federal Scientific Research Centre “Crystallography and Photonics” of Russian Academy of Sciences, Pionerskaya 2, Troitsk, 108840 Moscow, Russia; (N.M.); (A.S.); (V.G.)
| | - Fedor Potemkin
- Faculty of Physics, M. V. Lomonosov Moscow State University, Leninskie Gory bld.1/2, 119991 Moscow, Russia; (T.S.); (F.P.)
| | - Vyacheslav Gordienko
- Institute of Photon Technologies of Federal Scientific Research Centre “Crystallography and Photonics” of Russian Academy of Sciences, Pionerskaya 2, Troitsk, 108840 Moscow, Russia; (N.M.); (A.S.); (V.G.)
- Faculty of Physics, M. V. Lomonosov Moscow State University, Leninskie Gory bld.1/2, 119991 Moscow, Russia; (T.S.); (F.P.)
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22
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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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23
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Gutiérrez Ortiz FJ, Kruse A. The use of process simulation in supercritical fluids applications. REACT CHEM ENG 2020. [DOI: 10.1039/c9re00465c] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Modelling and simulation from micro- to macro-scale are needed to attain a broader commercialization of supercritical technologies.
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Affiliation(s)
- Francisco Javier Gutiérrez Ortiz
- Department of Chemical and Environmental Engineering
- Escuela Técnica Superior de Ingeniería
- University of Seville
- 41092 Sevilla
- Spain
| | - Andrea Kruse
- Department of Conversion Technologies and of Biobased Products
- Institute of Agricultural Engineering
- University of Hohenheim
- 70599 Stuttgart
- Germany
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24
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Zerón I, Torres-Arenas J, de Jesús E, Ramírez B, Benavides A. Discrete potential fluids in the supercritical region. J Mol Liq 2019. [DOI: 10.1016/j.molliq.2019.111518] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
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25
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Karalis K, Ludwig C, Niceno B. Supercritical water anomalies in the vicinity of the Widom line. Sci Rep 2019; 9:15731. [PMID: 31673024 PMCID: PMC6823507 DOI: 10.1038/s41598-019-51843-0] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2019] [Accepted: 09/05/2019] [Indexed: 12/21/2022] Open
Abstract
Supercritical water is used in a variety of chemical and industrial applications. As a consequence, a detailed knowledge of the structure-properties correlations is of uttermost importance. Although supercritical water was considered as a homogeneous fluid, recent studies revealed an anomalous behaviour due to nanoscale density fluctuations (inhomogeneity). The inhomogeneity is clearly demarked through the Widom line (maxima in response factions) and drastically affect the properties. In the current study the physical properties of supercritical water have been determined by classical molecular dynamics simulations using a variety of polarized and polarizable interatomic potentials. Their validity which was not available at supercritical conditions has been assessed based on the ability to reproduce experimental data. Overall, the polarized TIP4P/2005 model accurately predicted the properties of water in both liquid-like and gas-like regions. All interatomic potentials captured the anomalous behaviour providing a direct evidence of molecular-scale inhomogeneity.
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Affiliation(s)
- Konstantinos Karalis
- Laboratory for Scientific Computing and Modelling (LSM), NES Division, Paul Scherrer Institute, 5232, Villigen PSI, Switzerland.
| | - Christian Ludwig
- Laboratory for Bioenergy and Catalysis (LBK), ENE Division, Paul Scherrer Institute, 5232, Villigen PSI, Switzerland
- École Polytechnique Fédérale de Lausanne (EPFL), ENAC IIE GR-LUD, 1015, Lausanne, Switzerland
| | - Bojan Niceno
- Laboratory for Scientific Computing and Modelling (LSM), NES Division, Paul Scherrer Institute, 5232, Villigen PSI, Switzerland.
- Eidgenössische Technische Hochschule Zürich (ETHZ), MAVT-LKE, 8092, Zurich, Switzerland.
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26
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Visualization of supercritical water pseudo-boiling at Widom line crossover. Nat Commun 2019; 10:4114. [PMID: 31530816 PMCID: PMC6748934 DOI: 10.1038/s41467-019-12117-5] [Citation(s) in RCA: 45] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2019] [Accepted: 08/21/2019] [Indexed: 11/19/2022] Open
Abstract
Supercritical water is a green solvent used in many technological applications including materials synthesis, nuclear engineering, bioenergy, or waste treatment and it occurs in nature. Despite its relevance in natural systems and technical applications, the supercritical state of water is still not well understood. Recent theories predict that liquid-like (LL) and gas-like (GL) supercritical water are metastable phases, and that the so-called Widom line zone is marking the crossover between LL and GL behavior of water. With neutron imaging techniques, we succeed to monitor density fluctuations of supercritical water while the system evolves rapidly from LL to GL as the Widom line is crossed during isobaric heating. Our observations show that the Widom line of water can be identified experimentally and they are in agreement with the current theory of supercritical fluid pseudo-boiling. This fundamental understanding allows optimizing and developing new technologies using supercritical water as a solvent. Supercritical water exists in gas- and liquid-like forms, but these have not been distinguished yet at the macroscale. Here the authors investigate supercritical water interacting with microporous carbon by neutron imaging, and observe the coexistence of gas- and liquid-like states upon crossing the Widom line.
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27
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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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28
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Yoon TJ, Ha MY, Lee WB, Lee YW. A corresponding-state framework for the structural transition of supercritical fluids across the Widom delta. J Chem Phys 2019; 150:154503. [DOI: 10.1063/1.5086467] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Affiliation(s)
- Tae Jun Yoon
- School of Chemical and Biological Engineering, Institute of Chemical Processes, Seoul National University, Seoul 08826, South Korea
| | - Min Young Ha
- School of Chemical and Biological Engineering, Institute of Chemical Processes, Seoul National University, Seoul 08826, South Korea
| | - Won Bo Lee
- School of Chemical and Biological Engineering, Institute of Chemical Processes, Seoul National University, Seoul 08826, South Korea
| | - Youn-Woo Lee
- School of Chemical and Biological Engineering, Institute of Chemical Processes, Seoul National University, Seoul 08826, South Korea
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29
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Sun Y, DeJaco RF, Siepmann JI. Deep neural network learning of complex binary sorption equilibria from molecular simulation data. Chem Sci 2019; 10:4377-4388. [PMID: 31057764 PMCID: PMC6482883 DOI: 10.1039/c8sc05340e] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2018] [Accepted: 03/17/2019] [Indexed: 01/29/2023] Open
Abstract
We employed deep neural networks (NNs) as an efficient and intelligent surrogate of molecular simulations for complex sorption equilibria using probabilistic modeling. Canonical (N 1 N 2 VT) Gibbs ensemble Monte Carlo simulations were performed to model a single-stage equilibrium desorptive drying process for (1,4-butanediol or 1,5-pentanediol)/water and 1,5-pentanediol/ethanol from all-silica MFI zeolite and 1,5-pentanediol/water from all-silica LTA zeolite. A multi-task deep NN was trained on the simulation data to predict equilibrium loadings as a function of thermodynamic state variables. The NN accurately reproduces simulation results and is able to obtain a continuous isotherm function. Its predictions can be therefore utilized to facilitate optimization of desorption conditions, which requires a laborious iterative search if undertaken by simulation alone. Furthermore, it learns information about the binary sorption equilibria as hidden layer representations. This allows for application of transfer learning with limited data by fine-tuning a pretrained NN for a different alkanediol/solvent/zeolite system.
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Affiliation(s)
- Yangzesheng Sun
- Department of Chemistry and Chemical Theory Center , University of Minnesota , 207 Pleasant Street SE , Minneapolis , Minnesota 55455-0431 , USA . ; ; Tel: +1 (612) 624-1844
| | - Robert F DeJaco
- Department of Chemistry and Chemical Theory Center , University of Minnesota , 207 Pleasant Street SE , Minneapolis , Minnesota 55455-0431 , USA . ; ; Tel: +1 (612) 624-1844.,Department of Chemical Engineering and Materials Science , University of Minnesota , 412 Washington Avenue SE , Minneapolis , Minnesota 55455-0132 , USA
| | - J Ilja Siepmann
- Department of Chemistry and Chemical Theory Center , University of Minnesota , 207 Pleasant Street SE , Minneapolis , Minnesota 55455-0431 , USA . ; ; Tel: +1 (612) 624-1844.,Department of Chemical Engineering and Materials Science , University of Minnesota , 412 Washington Avenue SE , Minneapolis , Minnesota 55455-0132 , USA
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30
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Hestand NJ, Strong SE, Shi L, Skinner JL. Mid-IR spectroscopy of supercritical water: From dilute gas to dense fluid. J Chem Phys 2019; 150:054505. [DOI: 10.1063/1.5079232] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Affiliation(s)
- Nicholas J. Hestand
- Institute for Molecular Engineering, University of Chicago, Chicago, Illinois 60637, USA
| | - Steven E. Strong
- Institute for Molecular Engineering, University of Chicago, Chicago, Illinois 60637, USA
| | - Liang Shi
- School of Natural Sciences, University of California, Merced, California 95344, USA
| | - J. L. Skinner
- Institute for Molecular Engineering, University of Chicago, Chicago, Illinois 60637, USA
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31
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Yoon TJ, Ha MY, Lazar EA, Lee WB, Lee YW. Topological Characterization of Rigid-Nonrigid Transition across the Frenkel Line. J Phys Chem Lett 2018; 9:6524-6528. [PMID: 30293429 DOI: 10.1021/acs.jpclett.8b02715] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
The dynamics of supercritical fluids, a state of matter beyond the gas-liquid critical point, changes from diffusive to oscillatory motions at high pressure. This transition is believed to occur across a locus of thermodynamic states called the Frenkel line. The Frenkel line has been extensively investigated from the viewpoint of the dynamics, but its structural meaning is still not well-understood. This Letter interprets the mesoscopic picture of the Frenkel line entirely based on a topological and geometrical framework. This discovery makes it possible to understand the mechanism of rigid-nonrigid transition based not on the dynamics of individual atoms but on their instantaneous configurations. The topological classification method reveals that the percolation of solid-like structures occurs above the rigid-nonrigid crossover densities.
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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
| | - Emanuel A Lazar
- Materials Science and Engineering , University of Pennsylvania , Philadelphia , Pennsylvania 19104 , United States
| | - 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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32
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Strong SE, Shi L, Skinner JL. Percolation in supercritical water: Do the Widom and percolation lines coincide? J Chem Phys 2018; 149:084504. [DOI: 10.1063/1.5042556] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Affiliation(s)
- Steven E. Strong
- Institute for Molecular Engineering, University of Chicago, Chicago, Illinois 60637, USA
| | - Liang Shi
- School of Natural Sciences, University of California, Merced, California 95344, USA
| | - J. L. Skinner
- Institute for Molecular Engineering, University of Chicago, Chicago, Illinois 60637, USA
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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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34
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Yoon TJ, Ha MY, Lee WB, Lee YW. Probabilistic characterization of the Widom delta in supercritical region. J Chem Phys 2018; 149:014502. [DOI: 10.1063/1.5035106] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023] Open
Affiliation(s)
- Tae Jun Yoon
- School of Chemical and Biological Engineering, Institute of Chemical Processes, Seoul National University, Seoul 08826, South Korea
| | - Min Young Ha
- School of Chemical and Biological Engineering, Institute of Chemical Processes, Seoul National University, Seoul 08826, South Korea
| | - Won Bo Lee
- School of Chemical and Biological Engineering, Institute of Chemical Processes, Seoul National University, Seoul 08826, South Korea
| | - Youn-Woo Lee
- School of Chemical and Biological Engineering, Institute of Chemical Processes, Seoul National University, Seoul 08826, South Korea
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