1
|
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.
Collapse
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
| |
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
|
Pruteanu CG, Bannerman MN, Kirsz M, Lue L, Ackland GJ. From Atoms to Colloids: Does the Frenkel Line Exist in Discontinuous Potentials? ACS OMEGA 2023; 8:12144-12153. [PMID: 37033816 PMCID: PMC10077443 DOI: 10.1021/acsomega.2c08056] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 12/19/2022] [Accepted: 03/20/2023] [Indexed: 06/19/2023]
Abstract
The Frenkel line has been proposed as a crossover in the fluid region of phase diagrams between a "nonrigid" and a "rigid" fluid. It is generally described as a crossover in the dynamical properties of a material and as such has been described theoretically using a very different set of markers from those with which is it investigated experimentally. In this study, we have performed extensive calculations using two simple yet fundamentally different model systems: hard spheres and square-well potentials. The former has only hardcore repulsion, while the latter also includes a simple model of attraction. We computed and analyzed a series of physical properties used previously in simulations and experimental measurements and discuss critically their correlations and validity as to being able to uniquely and coherently locate the Frenkel line in discontinuous potentials.
Collapse
Affiliation(s)
- Ciprian G. Pruteanu
- SUPA,
School of Physics and Astronomy and Centre for Science at Extreme
Conditions, The University of Edinburgh, Edinburgh EH9 3JZ, United Kingdom
| | - Marcus N. Bannerman
- School
of Engineering, University of Aberdeen, Aberdeen AB24 3UE, United Kingdom
| | - Marcin Kirsz
- SUPA,
School of Physics and Astronomy and Centre for Science at Extreme
Conditions, The University of Edinburgh, Edinburgh EH9 3JZ, United Kingdom
| | - Leo Lue
- Department
of Chemical and Process Engineering, University
of Strathclyde, James
Weir Building, 75 Montrose Street, Glasgow G1 1XJ, United
Kingdom
| | - Graeme J. Ackland
- SUPA,
School of Physics and Astronomy and Centre for Science at Extreme
Conditions, The University of Edinburgh, Edinburgh EH9 3JZ, United Kingdom
| |
Collapse
|
4
|
Pruteanu CG, Loveday JS, Ackland GJ, Proctor JE. Krypton and the Fundamental Flaw of the Lennard-Jones Potential. J Phys Chem Lett 2022; 13:8284-8289. [PMID: 36036981 PMCID: PMC9465677 DOI: 10.1021/acs.jpclett.2c02004] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2022] [Accepted: 08/22/2022] [Indexed: 06/15/2023]
Abstract
We have performed a series of neutron scattering experiments on supercritical krypton. Our data and analysis allow us to characterize the Frenkel line crossover in this model monatomic fluid. The data from our measurements was analyzed using Empirical Potential Structure Refinement to determine the short- and medium-range structure of the fluids. We find evidence for several shells of neighbors which form approximately concentric rings of density about each atom. The ratio of second to first shell radius is significantly larger than in any crystal structure. Modeling krypton using a Lennard-Jones potential is shown to give significant errors, notably that the liquid is overstructured. The true potential appears to be longer ranged and with a softer core than the 6-12 powerlaws permit.
Collapse
Affiliation(s)
- Ciprian G. Pruteanu
- SUPA,
School of Physics and Astronomy and Centre for Science at Extreme
Conditions, The University of Edinburgh, Edinburgh EH9 3FD, U.K.
| | - John S. Loveday
- SUPA,
School of Physics and Astronomy and Centre for Science at Extreme
Conditions, The University of Edinburgh, Edinburgh EH9 3FD, U.K.
| | - Graeme J. Ackland
- SUPA,
School of Physics and Astronomy and Centre for Science at Extreme
Conditions, The University of Edinburgh, Edinburgh EH9 3FD, U.K.
| | - John E. Proctor
- Materials
& Physics Research Group, Newton Building, University of Salford, Manchester M5 4WT, U.K.
| |
Collapse
|
5
|
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.
Collapse
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
| |
Collapse
|
6
|
Bolmatov D. The Phonon Theory of Liquids and Biological Fluids: Developments and Applications. J Phys Chem Lett 2022; 13:7121-7129. [PMID: 35950307 DOI: 10.1021/acs.jpclett.2c01779] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
Among the three basic states of matter (solid, liquid, and gas), the liquid state has always eluded general theoretical approaches for describing liquid energy and heat capacity. In this Viewpoint, we derive the phonon theory of liquids and biological fluids stemming from Frenkel's microscopic picture of the liquid state. Specifically, the theory predicts the existence of phonon gaps in vibrational spectra of liquids and a thermodynamic boundary in the supercritical state. Direct experimental evidence reaffirming these theoretical predictions was achieved through a combination of techniques using static compression X-ray diffraction and inelastic X-ray scattering on deeply supercritical argon in a diamond anvil cell. Furthermore, these findings inspired and then led to the discovery of phonon gaps in liquid crystals (mesogens), block copolymers, and biological membranes. Importantly, phonon gaps define viscoelastic crossovers in cellular membranes responsible for lipid self-diffusion, lateral molecular-level stress propagation, and passive transmembrane transport of small molecules and solutes. Finally, molecular interactions mediated by external stimuli result in synaptic activity controlling biological membranes' plasticity resulting in learning and memory. Therefore, we also discuss learning and memory effects─equally important for neuroscience as well as for the development of neuromorphic devices─facilitated in biological membranes by external stimuli.
Collapse
Affiliation(s)
- Dima Bolmatov
- Department of Physics and Astronomy, University of Tennessee, Knoxville, Tennessee 37996, United States
- Shull Wollan Center, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, United States
| |
Collapse
|
7
|
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]
|
8
|
Abstract
It is demonstrated that the crossover between gas- and liquid-like regions on the phase diagram of the Lennard-Jones system occurs at a fixed value of the density divided by its value at the freezing point, ρ/ ρfr ≃ 0.35. This definition is consistent with other definitions proposed recently. As a result, a very simple practical expression for the gas-to-liquid crossover line emerges.
Collapse
Affiliation(s)
- S. A. Khrapak
- Joint Institute for High Temperatures, Russian Academy of Sciences, 125412 Moscow, Russia
| |
Collapse
|
9
|
Pruteanu CG, Kirsz M, Ackland GJ. Frenkel Line in Nitrogen Terminates at the Triple Point. J Phys Chem Lett 2021; 12:11609-11615. [PMID: 34812632 DOI: 10.1021/acs.jpclett.1c03206] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
Recent studies on supercritical nitrogen revealed clear changes in structural markers and dynamical properties when the coordination number approaches its maximum value. The line in P and T space where these changes occur is referred to as the Frenkel line. Here, we qualitatively reproduce such changes in the supercritical regime using the popular "optimized potential for liquid simulation" (OPLS) classical force field for molecular dynamics. Unfortunately, at 160 K, OPLS nitrogen predicts sublimation rather than producing a liquid phase; therefore, we developed our own force field to achieve quantitative agreement with experimental data. We confirm the asymptotic behavior of the coordination number on crossing the Frenkel line and note an associated change in the diffusion constant, consistent with the non-rigid to rigid liquid-like character of the "transition". The simulations allow us to track the Frenkel line to subcritical temperatures and demonstrate that it terminates at the triple point. This establishes the experimentally measurable changes, which could unequivocally determine the Frenkel line in other systems.
Collapse
Affiliation(s)
- Ciprian G Pruteanu
- Scottish Universities Physics Alliance (SUPA), School of Physics and Astronomy and Centre for Science at Extreme Conditions, The University of Edinburgh, Edinburgh EH9 3FD, United Kingdom
| | - Marcin Kirsz
- Scottish Universities Physics Alliance (SUPA), School of Physics and Astronomy and Centre for Science at Extreme Conditions, The University of Edinburgh, Edinburgh EH9 3FD, United Kingdom
| | - Graeme J Ackland
- Scottish Universities Physics Alliance (SUPA), School of Physics and Astronomy and Centre for Science at Extreme Conditions, The University of Edinburgh, Edinburgh EH9 3FD, United Kingdom
| |
Collapse
|
10
|
Yamaoka S, Hyeon-Deuk K. Distinct molecular dynamics dividing liquid-like and gas-like supercritical hydrogens. Phys Chem Chem Phys 2021; 23:22110-22118. [PMID: 34580684 DOI: 10.1039/d1cp02650j] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Understanding how a supercritical fluid is related to normal liquid and gas and separating it into liquid-like and gas-like regions are of fundamental and practical importance. Despite the usefulness of hydrogen storage, molecular dynamics images on supercritical hydrogens exhibiting strong nuclear quantum effects are scarce. Taking advantage of the non-empirical ab initio molecular dynamics method for hydrogen molecules, we found that, while radial distribution functions and diffusion show a monotonic change along the density, van Hove time correlation functions and intramolecular properties such as bond length and vibrational frequency exhibit the anomalous order crossing the Widom line. By demonstrating that the anomalous order stemmed from the largest deviations between liquid-like and gas-like solvations formed around the Widom line, we concluded that this supercritical fluid is a mixture of liquid and gas possessing heterogeneity. The obtained physical insights can be an index to monitor the supercriticality and to identify distinct liquid-like and gas-like supercritical fluids.
Collapse
Affiliation(s)
- Shutaro Yamaoka
- Department of Chemistry, Kyoto University, Kyoto 606-8502, Japan.
| | - Kim Hyeon-Deuk
- Department of Chemistry, Kyoto University, Kyoto 606-8502, Japan.
| |
Collapse
|
11
|
Cockrell C, Brazhkin VV, Trachenko K. Universal interrelation between dynamics and thermodynamics and a dynamically driven "c" transition in fluids. Phys Rev E 2021; 104:034108. [PMID: 34654136 DOI: 10.1103/physreve.104.034108] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2021] [Accepted: 08/26/2021] [Indexed: 06/13/2023]
Abstract
Our very wide survey of the supercritical phase diagram and its key properties reveals a universal interrelation between dynamics and thermodynamics and an unambiguous transition between liquidlike and gaslike states. This is seen in the master plot showing a collapse of the data representing the dependence of specific heat on key dynamical parameters in the system for many different paths on the phase diagram. As a result, the observed transition is path independent. We call it a "c" transition due to the c-shaped curve parametrizing the dependence of the specific heat on key dynamical parameters. The c transition has a fixed inversion point and provides a new structure to the phase diagram, operating deep in the supercritical state (up to, at least, 2000 times the critical pressure and 50 times the critical temperature). The data collapse and path independence as well as the existence of a special inversion point on the phase diagram are indicative of either of a sharp crossover or a new phase transition in the deeply supercritical state.
Collapse
Affiliation(s)
- C Cockrell
- School of Physics and Astronomy, Queen Mary University of London, Mile End Road, London, E1 4NS, United Kingdom
| | - V V Brazhkin
- Institute for High Pressure Physics, RAS, 108840 Troitsk, Moscow, Russia
| | - K Trachenko
- School of Physics and Astronomy, Queen Mary University of London, Mile End Road, London, E1 4NS, United Kingdom
| |
Collapse
|
12
|
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.
Collapse
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
| |
Collapse
|
13
|
Bell IH, Delage-Santacreu S, Hoang H, Galliero G. Dynamic Crossover in Fluids: From Hard Spheres to Molecules. J Phys Chem Lett 2021; 12:6411-6417. [PMID: 34232673 DOI: 10.1021/acs.jpclett.1c01594] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
We propose a simple and generic definition of a demarcation reconciling structural and dynamic frameworks when combined with the entropy scaling framework. This crossover line between gas- and liquid-like behaviors is defined as the curve for which an individual property, the contribution to viscosity due to molecules' translation, is exactly equal to a collective property, the contribution to viscosity due to molecular interactions. Such a definition is shown to be consistent with the one based on the minima of the kinematic viscosity. For the hard sphere, this is shown to be an exact solution. For Lennard-Jones spheres and dimers and for some simple real fluids, this relation holds very well. This crossover line passes nearby the critical point, and for all studied fluids, it is well captured by the critical excess entropy curve for atomic fluids, emphasizing the link between transport properties and local structure.
Collapse
Affiliation(s)
- Ian H Bell
- Applied Chemicals and Materials Division, National Institute of Standards and Technology, Boulder, Colorado 80305, United States
| | - Stéphanie Delage-Santacreu
- Université de Pau et des Pays de l'Adour, e2s UPPA, Laboratoire de Mathematiques et de leurs Applications de Pau (IPRA, CNRS UMR5142), Pau 64000, France
| | - Hai Hoang
- Institute of Fundamental and Applied Sciences, Duy Tan University, 10C Tran Nhat Duat Street, District 1, Ho Chi Minh City 700000, Vietnam
- Faculty of Natural Sciences, Duy Tan University, Da Nang 550000, Vietnam
| | - Guillaume Galliero
- Université de Pau et des Pays de l'Adour, e2s UPPA, TOTAL, CNRS, LFCR, UMR 5150, Laboratoire des fluides complexes et leurs reservoirs, Pau 64000, France
| |
Collapse
|
14
|
|
15
|
Cockrell C. Crossover of dynamical instability and chaos in the supercritical state. Phys Rev E 2020; 102:062206. [PMID: 33465999 DOI: 10.1103/physreve.102.062206] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2020] [Accepted: 11/24/2020] [Indexed: 06/12/2023]
Abstract
We calculate the maximal Lyapunov exponent for a bulk system of 256 Lennard-Jones particles in constant energy molecular dynamics simulations deep into the supercritical state. We find that the maximal Lyapunov exponent undergoes a crossover and that this crossover coincides with the dynamical crossover at the Frenkel line from liquid physics. We explain this crossover in terms of two different contributions to dynamical instability: diffusion in the liquidlike state below the Frenkel line and collisions in the gaslike state above. These results provide insight into the phase-space dynamics far from the melting line and densities where rare-gas approximation are inapplicable.
Collapse
Affiliation(s)
- C Cockrell
- School of Physics and Astronomy, Queen Mary University of London, London E1 4NS, United Kingdom
| |
Collapse
|
16
|
Cockrell C, Dicks OA, Brazhkin VV, Trachenko K. Pronounced structural crossover in water at supercritical pressures. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2020; 32:385102. [PMID: 32434172 DOI: 10.1088/1361-648x/ab94f1] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/07/2020] [Accepted: 05/20/2020] [Indexed: 06/11/2023]
Abstract
There have been ample studies of the many phases of H2O in both its solid and low pressure liquid states, and the transitions between them. Using molecular dynamics simulations we address the hitherto unexplored deeply supercritical pressures, where no qualitative transitions are thought to take place and where all properties are expected to vary smoothly. On the basis of these simulations we predict that water at supercritical pressures undergoes a structural crossover across the Frenkel line at pressures as high as 45 times the critical pressure. This provides a new insight into the water phase diagram and establishes a link between the structural and dynamical properties of supercritical water. Specifically, the crossover is demonstrated by a sharp and pronounced at low pressures, and smooth at high pressures, signified by changes in the pair distribution functions and local coordination which coincide with the dynamical transition (the loss of all oscillatory molecular motion) at the Frenkel line on the phase diagram.
Collapse
Affiliation(s)
- C Cockrell
- School of Physics and Astronomy, Queen Mary University of London, Mile End Road, London, E1 4NS, United Kingdom
| | - O A Dicks
- School of Physics and Astronomy, Queen Mary University of London, Mile End Road, London, E1 4NS, United Kingdom
| | - V V Brazhkin
- Institute for High Pressure Physics, RAS, 108840, Moscow, Russia
| | - K Trachenko
- School of Physics and Astronomy, Queen Mary University of London, Mile End Road, London, E1 4NS, United Kingdom
| |
Collapse
|
17
|
Cockrell CJ, Dicks O, Wang L, Trachenko K, Soper AK, Brazhkin VV, Marinakis S. Experimental and modeling evidence for structural crossover in supercritical CO_{2}. Phys Rev E 2020; 101:052109. [PMID: 32575221 DOI: 10.1103/physreve.101.052109] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2020] [Accepted: 04/08/2020] [Indexed: 06/11/2023]
Abstract
The physics of supercritical states is understood to a much lesser degree compared to subcritical liquids. Carbon dioxide, in particular, has been intensely studied, yet little is known about the supercritical part of its phase diagram. Here, we combine neutron scattering experiments and molecular dynamics simulations and demonstrate the structural crossover at the Frenkel line. The crossover is seen at pressures as high as 14 times the critical pressure and is evidenced by changes of the main features of the structure factor and pair distribution functions.
Collapse
Affiliation(s)
- Cillian J Cockrell
- School of Physics and Astronomy, Queen Mary University of London, Mile End Road, London E1 4NS, United Kingdom
| | | | | | | | - Alan K Soper
- ISIS Facility, STFC Rutherford Appleton Laboratory, Harwell Campus, Didcot, Oxon OX11 0QX, United Kingdom
| | | | - Sarantos Marinakis
- School of Health, Sport and Bioscience, University of East London, Stratford Campus, Water Lane, London E15 4LZ, United Kingdom and Department of Chemistry and Biochemistry, School of Biological and Chemical Sciences, Queen Mary University of London, Joseph Priestley Building, Mile End Road, London E1 4NS, United Kingdom
| |
Collapse
|