1
|
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.
Collapse
Affiliation(s)
- Ioannis Skarmoutsos
- Laboratory of Physical Chemistry, Department of Chemistry, University of Ioannina, 45110 Ioannina, Greece
| |
Collapse
|
2
|
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.
Collapse
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
| |
Collapse
|
3
|
Garkul A, Stegailov V. Molecular dynamics analysis of elastic properties and new phase formation during amorphous ices transformations. Sci Rep 2022; 12:13325. [PMID: 35922440 PMCID: PMC9349219 DOI: 10.1038/s41598-022-17666-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2022] [Accepted: 07/28/2022] [Indexed: 12/02/2022] Open
Abstract
Unlike conventional first-order phase transitions, the kinetics of amorphous-amorphous transitions has been much less studied. The ultrasonic experiments on the transformations between low-density and high-density amorphous ice induced by pressure or heating provided the pressure and temperature dependencies of elastic moduli. In this article, we make an attempt to build a microscopic picture of these experimentally studied transformations using the molecular dynamics method with the TIP4P/Ice water model. We study carefully the dependence of the results of elastic constants calculations on the deformation rates. The system size effects are considered as well. The comparison with the experimental data enriches our understanding of the transitions observed. Our modeling gives new information about the formation mechanisms of new phase clusters during the transition between low-density and high-density amorphous ices. We analyse the applicability of the term "nucleation" for these processes.
Collapse
Affiliation(s)
- Anastasiia Garkul
- Joint Institute for High Temperatures of the Russian Academy of Sciences, 125412, Moscow, Russia.
- Moscow Institute of Physics and Technology (National Research University), 141701, Dolgoprudny, Russia.
| | - Vladimir Stegailov
- Joint Institute for High Temperatures of the Russian Academy of Sciences, 125412, Moscow, Russia
- Moscow Institute of Physics and Technology (National Research University), 141701, Dolgoprudny, Russia
- National Research University Higher School of Economics, 109028, Moscow, Russia
| |
Collapse
|
4
|
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]
|
5
|
Rezaei T, Nazarpour V, Shahini N, Bahmani S, Shahkar A, Abdihaji M, Ahmadi S, Shahdost FT. A universal methodology for reliable predicting the non-steroidal anti-inflammatory drug solubility in supercritical carbon dioxide. Sci Rep 2022; 12:1043. [PMID: 35058504 PMCID: PMC8776948 DOI: 10.1038/s41598-022-04942-4] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2021] [Accepted: 01/04/2022] [Indexed: 12/19/2022] Open
Abstract
Understanding the drug solubility behavior is likely the first essential requirement for designing the supercritical technology for pharmaceutical processing. Therefore, this study utilizes different machine learning scenarios to simulate the solubility of twelve non-steroidal anti-inflammatory drugs (NSAIDs) in the supercritical carbon dioxide (SCCO2). The considered NSAIDs are Fenoprofen, Flurbiprofen, Ibuprofen, Ketoprofen, Loxoprofen, Nabumetone, Naproxen, Nimesulide, Phenylbutazone, Piroxicam, Salicylamide, and Tolmetin. Physical characteristics of the drugs (molecular weight and melting temperature), operating conditions (pressure and temperature), and solvent property (SCCO2 density) are effectively used to estimate the drug solubility. Monitoring and comparing the prediction accuracy of twelve intelligent paradigms from three categories (artificial neural networks, support vector regression, and hybrid neuro-fuzzy) approves that adaptive neuro-fuzzy inference is the best tool for the considered task. The hybrid optimization strategy adjusts the cluster radius of the subtractive clustering membership function to 0.6111. This model estimates 254 laboratory-measured solubility data with the AAPRE = 3.13%, MSE = 2.58 × 10–9, and R2 = 0.99919. The leverage technique confirms that outliers may poison less than four percent of the experimental data. In addition, the proposed hybrid paradigm is more reliable than the equations of state and available correlations in the literature. Experimental measurements, model predictions, and relevancy analyses justified that the drug solubility in SCCO2 increases by increasing temperature and pressure. The results show that Ibuprofen and Naproxen are the most soluble and insoluble drugs in SCCO2, respectively.
Collapse
|
6
|
Bonakala S, Hasan MI. Comparative study of external electric field and potential effects on liquid water ions. Mol Phys 2021. [DOI: 10.1080/00268976.2021.1998689] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
Affiliation(s)
- Satyanarayana Bonakala
- Department of Electrical Engineering and Electronics, Centre for Plasma Microbiology, University of Liverpool, Liverpool, UK
| | - Mohammad I. Hasan
- Department of Electrical Engineering and Electronics, Centre for Plasma Microbiology, University of Liverpool, Liverpool, UK
| |
Collapse
|
7
|
Corsaro C, Fazio E. From Critical Point to Critical Point: The Two-States Model Describes Liquid Water Self-Diffusion from 623 to 126 K. Molecules 2021; 26:molecules26195899. [PMID: 34641442 PMCID: PMC8512083 DOI: 10.3390/molecules26195899] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2021] [Revised: 09/23/2021] [Accepted: 09/26/2021] [Indexed: 12/02/2022] Open
Abstract
Liquid’s behaviour, when close to critical points, is of extreme importance both for fundamental research and industrial applications. A detailed knowledge of the structural–dynamical correlations in their proximity is still today a target to reach. Liquid water anomalies are ascribed to the presence of a second liquid–liquid critical point, which seems to be located in the very deep supercooled regime, even below 200 K and at pressure around 2 kbar. In this work, the thermal behaviour of the self-diffusion coefficient for liquid water is analyzed, in terms of a two-states model, for the first time in a very wide thermal region (126 K < T < 623 K), including those of the two critical points. Further, the corresponding configurational entropy and isobaric-specific heat have been evaluated within the same interval. The two liquid states correspond to high and low-density water local structures that play a primary role on water dynamical behavior over 500 K.
Collapse
|
8
|
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.
Collapse
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
| |
Collapse
|
9
|
The temperature dependence of the frequency of longitudinal excitations in liquid along isobars: Simple liquid and water. J Mol Liq 2021. [DOI: 10.1016/j.molliq.2021.116450] [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]
|
10
|
Maxim F, Karalis K, Boillat P, Banuti DT, Marquez Damian JI, Niceno B, Ludwig C. Thermodynamics and Dynamics of Supercritical Water Pseudo-Boiling. ADVANCED SCIENCE (WEINHEIM, BADEN-WURTTEMBERG, GERMANY) 2021; 8:2002312. [PMID: 33552857 PMCID: PMC7856905 DOI: 10.1002/advs.202002312] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 06/22/2020] [Revised: 10/12/2020] [Indexed: 06/12/2023]
Abstract
Supercritical fluid pseudo-boiling (PB), recently brought to the attention of the scientific community, is the phenomenon occurring when fluid changes its structure from liquid-like (LL) to gas-like (GL) states across the Widom line. This work provides the first quantitative analysis on the thermodynamics and the dynamics of water's PB, since the understanding of this phase transition is mandatory for the successful implementation of technologies using supercritical water (scH2O) for environmental, energy, and nanomaterial applications. The study combines computational techniques with in situ neutron imaging measurements. The results demonstrate that, during isobaric heating close to the critical point, while water density drops by a factor of three in the PB transitional region, the system needs >16 times less energy to increase its temperature by 1 K than to change its structure from LL to GL phase. Above the PB-Widom line, the structure of LL water consists mainly of tetramers and trimers, while below the line mostly dimers and monomers form in the GL phase. At atomic level, the PB dynamics are similar to those of the subcritical water vaporization. This fundamental knowledge has great impact on water science, as it helps to establish the structure-properties relationship of scH2O.
Collapse
Affiliation(s)
- Florentina Maxim
- Laboratory for Chemical Thermodynamics“Ilie Murgulescu” Institute of Physical ChemistrySplaiul Independentei 202Bucharest060021Romania
- Laboratory for Bioenergy and Catalysis (LBK)ENE DivisionPaul Scherrer InstituteVilligen PSI5232Switzerland
| | | | - Pierre Boillat
- Electrochemistry Laboratory (LEC)ENE DivisionPaul Scherrer InstituteVilligen PSI5232Switzerland
- Laboratory for Neutron Scattering and Imaging (LNS)NUM DivisionPaul Scherrer InstituteVilligen PSI5232Switzerland
| | - Daniel T. Banuti
- Department of Mechanical EngineeringThe University of New MexicoMSC01 1150AlbuquerqueNM87131USA
| | | | - Bojan Niceno
- Laboratory for Scientific Computing and Modelling (LSM)NES DivisionPaul Scherrer InstituteVilligen PSI5232Switzerland
- Eidgenössische Technische Hochschule Zürich (ETHZ)MAVT‐LKEZurich8092Switzerland
| | - Christian Ludwig
- Laboratory for Bioenergy and Catalysis (LBK)ENE DivisionPaul Scherrer InstituteVilligen PSI5232Switzerland
- École Polytechnique Fédérale de Lausanne (EPFL)ENAC IIE GR‐LUDLausanne1015Switzerland
| |
Collapse
|
11
|
Fomin YD. Dispersion of acoustic excitations in tetrahedral liquids. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2020; 32:395101. [PMID: 32452832 DOI: 10.1088/1361-648x/ab962e] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/18/2019] [Accepted: 05/22/2020] [Indexed: 06/11/2023]
Abstract
Investigation of the longitudinal and transverse excitations in liquids is of great importance for understanding the fundamentals of the liquid state of matter. One of the important questions is the temperature and density dependence of the frequency of the excitations. In our recent works it was shown that while in simple liquids the frequency of longitudinal excitations increases when the temperature is increased isochorically, in water the frequency can anomalously decrease with the temperature increase. In the present manuscript we study the dispersion curves of longitudinal and transverse excitations of water and liquid silicon modelled by Stillinger-Weber (SW) potential. We show that both in liquid silicon and SW model of water the frequencies of longitudinal excitations slightly increase with temperature which is in contrast to the results for SPC/E model of water.
Collapse
|
12
|
Yoon TJ, Patel LA, Ju T, Vigil MJ, Findikoglu AT, Currier RP, Maerzke KA. Thermodynamics, dynamics, and structure of supercritical water at extreme conditions. Phys Chem Chem Phys 2020; 22:16051-16062. [DOI: 10.1039/d0cp02288h] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Abstract
Molecular dynamics (MD) simulations to understand the thermodynamic, dynamic, and structural changes in supercritical water across the Frenkel line and the melting line have been performed.
Collapse
Affiliation(s)
| | | | - Taeho Ju
- Los Alamos National Laboratory
- Los Alamos
- USA
| | | | | | | | | |
Collapse
|
13
|
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.
Collapse
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.
| |
Collapse
|
14
|
Fomin Y, Tsiok E, Ryzhov V, Brazhkin V. Anomalous behavior of dispersion of longitudinal and transverse collective excitations in water. J Mol Liq 2019. [DOI: 10.1016/j.molliq.2019.110992] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
|
15
|
Kryuchkov NP, Mistryukova LA, Brazhkin VV, Yurchenko SO. Excitation spectra in fluids: How to analyze them properly. Sci Rep 2019; 9:10483. [PMID: 31324848 PMCID: PMC6642218 DOI: 10.1038/s41598-019-46979-y] [Citation(s) in RCA: 25] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2019] [Accepted: 07/09/2019] [Indexed: 11/25/2022] Open
Abstract
Although the understanding of excitation spectra in fluids is of great importance, it is still unclear how different methods of spectral analysis agree with each other and which of them is suitable in a wide range of parameters. Here, we show that the problem can be solved using a two-oscillator model to analyze total velocity current spectra, while other considered methods, including analysis of the spectral maxima and single mode analysis, yield rough results and become unsuitable at high temperatures and wavenumbers. To prove this, we perform molecular dynamics (MD) simulations and calculate excitation spectra in Lennard-Jones and inverse-power-law fluids at different temperatures, both in 3D and 2D cases. Then, we analyze relations between thermodynamic and dynamic features of fluids at (Frenkel) crossover from a liquid- to gas-like state and find that they agree with each other in the 3D case and strongly disagree in 2D systems due to enhanced anharmonicity effects. The results provide a significant advance in methods for detail analysis of collective fluid dynamics spanning fields from soft condensed matter to strongly coupled plasmas.
Collapse
Affiliation(s)
- Nikita P Kryuchkov
- Bauman Moscow State Technical University, 2nd Baumanskaya street 5, Moscow, 105005, Russia
| | - Lukiya A Mistryukova
- Bauman Moscow State Technical University, 2nd Baumanskaya street 5, Moscow, 105005, Russia
| | - Vadim V Brazhkin
- Institute for High Pressure Physics RAS, Kaluzhskoe shosse, 14, Troitsk, Moscow, 108840, Russia
| | - Stanislav O Yurchenko
- Bauman Moscow State Technical University, 2nd Baumanskaya street 5, Moscow, 105005, Russia.
| |
Collapse
|
16
|
Ploetz EA, Smith PE. Gas or Liquid? The Supercritical Behavior of Pure Fluids. J Phys Chem B 2019; 123:6554-6563. [DOI: 10.1021/acs.jpcb.9b04058] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Elizabeth A. Ploetz
- Department of Chemistry, Kansas State University, 213 CBC Building, 1212 Mid Campus Dr. North, Manhattan, Kansas 66506-0401, United States
| | - Paul E. Smith
- Department of Chemistry, Kansas State University, 213 CBC Building, 1212 Mid Campus Dr. North, Manhattan, Kansas 66506-0401, United States
| |
Collapse
|
17
|
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
| |
Collapse
|
18
|
Fomin YD, Ryzhov VN, Tsiok EN, Proctor JE, Prescher C, Prakapenka VB, Trachenko K, Brazhkin VV. Dynamics, thermodynamics and structure of liquids and supercritical fluids: crossover at the Frenkel line. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2018; 30:134003. [PMID: 29443011 DOI: 10.1088/1361-648x/aaaf39] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
We review recent work aimed at understanding dynamical and thermodynamic properties of liquids and supercritical fluids. The focus of our discussion is on solid-like transverse collective modes, whose evolution in the supercritical fluids enables one to discuss the main properties of the Frenkel line separating rigid liquid-like and non-rigid gas-like supercritical states. We subsequently present recent experimental evidence of the Frenkel line showing that structural and dynamical crossovers are seen at a pressure and temperature corresponding to the line as predicted by theory and modelling. Finally, we link dynamical and thermodynamic properties of liquids and supercritical fluids by the new calculation of liquid energy governed by the evolution of solid-like transverse modes. The disappearance of those modes at high temperature results in the observed decrease of heat capacity.
Collapse
Affiliation(s)
- Yu D Fomin
- Institute for High Pressure Physics, Russian Academy of Sciences, Troitsk 108840, Moscow, Russia
| | | | | | | | | | | | | | | |
Collapse
|
19
|
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.
Collapse
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
| |
Collapse
|
20
|
Schienbein P, Marx D. Liquid–Vapor Phase Diagram of RPBE-D3 Water: Electronic Properties along the Coexistence Curve and in the Supercritical Phase. J Phys Chem B 2017; 122:3318-3329. [DOI: 10.1021/acs.jpcb.7b09761] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Affiliation(s)
- Philipp Schienbein
- Lehrstuhl für Theoretische Chemie, Ruhr-Universität Bochum, 44780 Bochum, Germany
| | - Dominik Marx
- Lehrstuhl für Theoretische Chemie, Ruhr-Universität Bochum, 44780 Bochum, Germany
| |
Collapse
|
21
|
Fomin YD, Ryzhov VN, Tsiok EN, Brazhkin VV. Excitation spectra of liquid iron up to superhigh temperatures. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2017; 29:345401. [PMID: 28653958 DOI: 10.1088/1361-648x/aa7c0e] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
Investigation of excitation spectra of liquids is one of the hot test topics nowadays. In particular, recent experimental works showed that liquid metals can demonstrate transverse excitations and positive sound dispersion. However, the theoretical description of these experimental observations is still missing. Here we report a molecular dynamics study of excitation spectra of liquid iron. We compare the results with available experimental data to justify the method. After that we perform calculations for high temperatures to find the location of the Frenkel line introduced in our previous works.
Collapse
Affiliation(s)
- Yu D Fomin
- Institute for High Pressure Physics RAS, Kaluzhskoe shosse, 14, Troitsk, Moscow, 108840, Russia
| | | | | | | |
Collapse
|
22
|
Śmiechowski M, Schran C, Forbert H, Marx D. Correlated Particle Motion and THz Spectral Response of Supercritical Water. PHYSICAL REVIEW LETTERS 2016; 116:027801. [PMID: 26824567 DOI: 10.1103/physrevlett.116.027801] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/30/2015] [Indexed: 06/05/2023]
Abstract
Molecular dynamics simulations of supercritical water reveal distinctly different distance-dependent modulations of dipolar response and correlations in particle motion compared to ambient conditions. The strongly perturbed H-bond network of water at supercritical conditions allows for considerable translational and rotational freedom of individual molecules. These changes give rise to substantially different infrared spectra and vibrational density of states at THz frequencies for densities above and below the Widom line that separates percolating liquidlike and clustered gaslike supercritical water.
Collapse
Affiliation(s)
- Maciej Śmiechowski
- Department of Physical Chemistry, Chemical Faculty, Gdańsk University of Technology, Narutowicza 11/12, 80-233 Gdańsk, Poland and Lehrstuhl für Theoretische Chemie, Ruhr-Universität Bochum, 44780 Bochum, Germany
| | - Christoph Schran
- Lehrstuhl für Theoretische Chemie, Ruhr-Universität Bochum, 44780 Bochum, Germany
| | - Harald Forbert
- Lehrstuhl für Theoretische Chemie, Ruhr-Universität Bochum, 44780 Bochum, Germany
| | - Dominik Marx
- Lehrstuhl für Theoretische Chemie, Ruhr-Universität Bochum, 44780 Bochum, Germany
| |
Collapse
|