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Bryk T, Ruocco G, Seitsonen AP. Stress fluctuations and adiabatic speed of sound in liquids: a simple way to estimate it from ab initio simulations. Sci Rep 2023; 13:18042. [PMID: 37872279 PMCID: PMC10593855 DOI: 10.1038/s41598-023-45338-2] [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: 07/28/2023] [Accepted: 10/18/2023] [Indexed: 10/25/2023] Open
Abstract
One of the fundamental quantities in dynamics of the liquid state, the adiabatic speed of sound [Formula: see text], is extremely difficult to predict from computer simulations, especially in ab initio simulations. Here we derive an expression for the instantaneous correlator of fluctuations of longitudinal component of stress tensor, which contains [Formula: see text] along with others quantities easy accessible via classical and ab initio computer simulations. We show that the proposed methodology works well in the case of Lennard-Jones and soft-sphere simple fluids, Kr-Ar liquid mixture in connection with simulations with effective pair interactions as well as for liquid Sb, fluid Hg and molten NaCl from ab initio simulations.
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Affiliation(s)
- Taras Bryk
- Institute for Condensed Matter Physics of National Academy of Sciences of Ukraine, Lviv, 79011, Ukraine.
- Institute of Applied Mathematics and Fundamental Sciences, Lviv National Polytechnic University, Lviv, 79013, Ukraine.
| | - Giancarlo Ruocco
- Center for Life Nano Science @Sapienza, Istituto Italiano di Tecnologia, 00161, Rome, Italy
- Dipartimento di Fisica, Universita' di Roma "La Sapienza", 00185, Rome, Italy
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Wax JF, Mocchetti E. Simulation study of the collective excitations in liquid sodium under high pressure. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2023; 35. [PMID: 37075771 DOI: 10.1088/1361-648x/acce8b] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/19/2022] [Accepted: 04/19/2023] [Indexed: 05/03/2023]
Abstract
The dynamic structure of liquid sodium is investigated using classical molecular dynamics simulations over a wide range of densities (from 739 to 4177 kg m-3). The interactions are described using screened pseudopotential formalism with Fiolhais model of electron-ion interaction. The effective pair potentials obtained are validated by comparing the predicted static structure, coordination number, self-diffusion coefficients and spectral density of the velocity autocorrelation function with results fromab initiosimulations at the same state points. Both longitudinal and transverse collective excitations are computed from the corresponding structure functions and their evolution with density is investigated. The frequency of the longitudinal excitations increases with density, as well as the sound speed, which is extracted from their dispersion curves. The frequency of the transverse excitations also increases with density, but they cannot propagate over macroscopic distances and the propagation gap clearly appears. The values of the viscosity, which are extracted from these transverse functions are in good agreement with available results computed from stress autocorrelation functions.
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Bryk T, Ilenkov IM, Seitsonen AP. Quasi-bound atoms in collective dynamics of liquid Sb. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2023; 35:154003. [PMID: 36735962 DOI: 10.1088/1361-648x/acb8f6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/29/2022] [Accepted: 02/03/2023] [Indexed: 06/18/2023]
Abstract
We report anab initiosimulation and theoretical study of collective dynamics in liquid Sb at 973 K. An application of the GCM (generalized collective modes) theoretical approach to analysis of simulation-derived time correlation functions resulted in two types of propagating eigenmodes. We found that the almost flat dispersion of the high-frequency branch of propagating modes can be explained by out-of-phase oscillations of nearest neighbors which form quasi-bound atomic pairs for at least 30 ps. We discuss the features of collective dynamics in non-simple metallic melts containing quasi-bound pairs.
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Affiliation(s)
- T Bryk
- Institute for Condensed Matter Physics of the National Academy of Sciences of Ukraine, 1 Svientsitskii Street, UA-79011 Lviv, Ukraine
- Institute of Applied Mathematics and Fundamental Sciences, Lviv Polytechnic National University, UA-79013 Lviv, Ukraine
| | - I-M Ilenkov
- Institute for Condensed Matter Physics of the National Academy of Sciences of Ukraine, 1 Svientsitskii Street, UA-79011 Lviv, Ukraine
| | - A P Seitsonen
- Département de Chimie, École Normale Supérieure, 24 rue Lhomond, F-75005 Paris, France
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Guarini E, Neumann M, De Francesco A, Formisano F, Cunsolo A, Montfrooij W, Colognesi D, Bafile U. Onset of collective excitations in the transverse dynamics of simple fluids. Phys Rev E 2023; 107:014139. [PMID: 36797969 DOI: 10.1103/physreve.107.014139] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2022] [Accepted: 01/10/2023] [Indexed: 06/18/2023]
Abstract
A thorough analysis of the transverse current autocorrelation function obtained by molecular dynamics simulations of a dense Lennard-Jones fluid reveals that even such a simple system is characterized by a varied dynamical behavior with changing length scale. By using the exponential expansion theory, we provide a full account of the time correlation at wavevectors Q between the upper boundary of the hydrodynamic region and Q_{p}/2, with Q_{p} being the position of the main peak of the static structure factor. In the Q range studied, we identify and accurately locate the wavevector at which shear wave propagation starts to take place, and show clearly how this phenomenon may be represented by a damped harmonic oscillator changing, in a continuous way, from an overdamped to an underdamped condition. The decomposition into exponential modes allows one to convincingly establish not only the crossover related to the onset of transverse waves but, surprisingly, also the existence of a second pair of modes equivalent to another oscillator that undergoes, at higher Q values, a similarly smooth over to underdamped transition.
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Affiliation(s)
- Eleonora Guarini
- Dipartimento di Fisica e Astronomia, Università degli Studi di Firenze, via G. Sansone 1, I-50019 Sesto Fiorentino, Italy
| | - Martin Neumann
- Fakultät für Physik der Universität Wien, Kolingasse 14-16, A-1090 Wien, Austria
| | - Alessio De Francesco
- CNR-IOM & INSIDE@ILL c/o Operative Group in Grenoble (OGG) F-38042 Grenoble, France and Institut Laue Langevin (ILL), F-38042 Grenoble, France
| | - Ferdinando Formisano
- CNR-IOM & INSIDE@ILL c/o Operative Group in Grenoble (OGG) F-38042 Grenoble, France and Institut Laue Langevin (ILL), F-38042 Grenoble, France
| | - Alessandro Cunsolo
- Department of Physics, University of Wisconsin at Madison, 1150 University Avenue, Madison, Wisconsin 53706, United States
| | - Wouter Montfrooij
- Department of Physics and Astronomy, University of Missouri, Columbia, Missouri 65211, United States
| | - Daniele Colognesi
- Consiglio Nazionale delle Ricerche, Istituto di Fisica Applicata "Nello Carrara", via Madonna del Piano 10, I-50019 Sesto Fiorentino, Italy
| | - Ubaldo Bafile
- Consiglio Nazionale delle Ricerche, Istituto di Fisica Applicata "Nello Carrara", via Madonna del Piano 10, I-50019 Sesto Fiorentino, Italy
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5
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Collective dynamics in liquid Si under high pressure above the melting line minimum. J Mol Liq 2022. [DOI: 10.1016/j.molliq.2022.121116] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
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Petrillo C, Sacchetti F. Future applications of the high-flux thermal neutron spectroscopy: the ever-green case of collective excitations in liquid metals. ADVANCES IN PHYSICS: X 2021. [DOI: 10.1080/23746149.2021.1871862] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022] Open
Affiliation(s)
- Caterina Petrillo
- Department of Physics & Earth Science, University of Perugia, Perugia, Italy
| | - Francesco Sacchetti
- Department of Physics & Earth Science, University of Perugia, Perugia, Italy
- National Research Council, Institute IOM-CNR, Perugia, Italy
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Del Rio BG, González LE, González DJ. First principles study of liquid uranium at temperatures up to 2050 K. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2020; 32:304001. [PMID: 32163938 DOI: 10.1088/1361-648x/ab7f6f] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Uranium compounds are used as fissile materials in nuclear reactors. In present day reactors the most used nuclear fuel is uranium dioxide, but in generation-IV reactors other compounds are also being considered, such as uranium carbide and uranium mononitride. Upon possible accidents where the coolant would not circulate or be lost the core of the reactor would reach very high temperatures, and therefore it is essential to understand the behaviour of the nuclear fuel under such conditions for proper risk assessment. We consider here molten metallic uranium at several temperatures ranging from 1455 to 2050 K. Even though metallic uranium is not a candidate for nuclear fuel it could nevertheless be produced due to the thermochemical instability of uranium nitride at high temperatures. We use first principles techniques to analyse the behaviour of this system and obtain basic structural and dynamic properties, as well as some thermodynamic and transport properties, including atomic diffusion and viscosity.
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Affiliation(s)
- Beatriz G Del Rio
- Departamento de Física Teórica, Universidad de Valladolid, Valladolid, Spain
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Del Rio BG, Pascual C, González LE, González DJ. Structure and dynamics of the liquid 3d transition metals near melting. An ab initio study. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2020; 32:214005. [PMID: 31972549 DOI: 10.1088/1361-648x/ab6f16] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
The static and dynamic properties of several bulk liquid 3d transition metals at thermodynamic conditions near their respective melting points have been evaluated by using ab initio molecular dynamics simulations. The calculated static structure factors show an asymmetric second peak followed by a more or less marked shoulder which points to a sizeable amount of icosahedral local order. Special attention is devoted to the analysis of the longitudinal and transverse current spectral functions and the corresponding dispersion of collective excitations. For some metals, we have found the existence of two branches of transverse collective excitations in the second pseudo-Brillouin zone. Finally, results are also reported for several transport coefficients.
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Affiliation(s)
- Beatriz G Del Rio
- Departamento de Física Teórica, Universidad de Valladolid, Valladolid, Spain
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Jakse N, Bryk T. Pressure evolution of transverse collective excitations in liquid Al along the melting line. J Chem Phys 2019; 151:034506. [PMID: 31325928 DOI: 10.1063/1.5099099] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Evolution of structure and dynamics of liquid Al with pressure along the melting line up to 300 GPa has been studied by means of ab initio molecular dynamics simulations. An analysis of structural properties shows that liquid Al undergoes uniform compression with pressure associated with a competition of the existing icosahedral local order with bcc ordering above 200 GPa. Dispersion of collective excitations indicates the presence of two branches of transverse nonpropagative modes in the second pseudo-Brillouin zone. Under pressure, the second high-frequency branch manifests as the second peak position in transverse current correlation functions, while, for ambient pressure, it corresponds to a smeared-out high-frequency shoulder. We report a correspondence of the peak locations in vibrational density of states with these two transverse collective excitations as well as their linear evolution with density.
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Affiliation(s)
- Noël Jakse
- Univ. Grenoble Alpes, CNRS, Grenoble INP, SIMaP, F-38000 Grenoble, France
| | - Taras Bryk
- Institute for Condensed Matter Physics of the National Academy of Sciences of Ukraine, 1 Svientsitskii Street, UA-79011 Lviv, Ukraine
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del Rio BG, Chen M, González LE, Carter EA. Orbital-free density functional theory simulation of collective dynamics coupling in liquid Sn. J Chem Phys 2018; 149:094504. [DOI: 10.1063/1.5040697] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Affiliation(s)
- Beatriz G. del Rio
- Departamento de Física Teórica, Atómica y Óptica, Universidad de Valladolid, 47011 Valladolid, Spain
- Department of Mechanical and Aerospace Engineering, Princeton University, Princeton, New Jersey 08544-5263, USA
| | - Mohan Chen
- Department of Physics, Temple University, Philadelphia, Pennsylvania 19122, USA
| | - Luis E. González
- Departamento de Física Teórica, Atómica y Óptica, Universidad de Valladolid, 47011 Valladolid, Spain
| | - Emily A. Carter
- School of Engineering and Applied Science, Princeton University, Princeton, New Jersey 08544-5263, USA
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Acoustic Anomalies and Fast Relaxation Dynamics of Amorphous Progesterone as Revealed by Brillouin Light Scattering. MATERIALS 2017; 10:ma10121426. [PMID: 29240692 PMCID: PMC5744361 DOI: 10.3390/ma10121426] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/14/2017] [Revised: 12/10/2017] [Accepted: 12/13/2017] [Indexed: 11/17/2022]
Abstract
The amorphous state of pharmaceuticals has attracted much attention due to its high bioavailability and other advantages. The stability of the amorphous state in relation with the local molecular mobility is important from both fundamental and practical points of view. The acoustic properties of amorphous progesterone, one of the representative steroid hormones, were investigated by using a Brillouin inelastic light scattering technique. The Brillouin spectrum of the longitudinal acoustic mode exhibited distinct changes at the glass transition and the cold-crystallization temperatures. The acoustic dispersions of the longitudinal sound velocity and the acoustic absorption coefficient were attributed to the fast and possibly the secondary relaxation processes in the glassy and supercooled liquid states, while the structural relaxation process was considered as the dominant origin for the significant acoustic damping observed even in the liquid phase. The persisting acoustic dispersion in the liquid state was attributed to the single-molecule nature of the progesterone which does not exhibit hydrogen bonds in the condensed states.
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Bryk T, Huerta A, Hordiichuk V, Trokhymchuk AD. Non-hydrodynamic transverse collective excitations in hard-sphere fluids. J Chem Phys 2017; 147:064509. [PMID: 28810767 DOI: 10.1063/1.4997640] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Collective excitations in hard-sphere fluids were studied in a wide range of wave numbers and packing fractions η by means of molecular dynamics simulations. We report the observation of non-hydrodynamic transverse excitations for packing fractions η≥0.395 in the shape of transverse current spectral functions. Dispersion of longitudinal excitations in the whole range of packing fractions shows a negative deviation from the linear hydrodynamic law with increasing wave numbers even for dense hard-sphere fluids where the transverse excitations were observed. These results do not support a recent proposal within the "Frenkel line" approach that the positive sound dispersion in liquids is defined by transverse excitations. We report calculations of the cutoff "Frenkel frequencies" for transverse excitations in hard-sphere fluids and discuss their consistency with the estimated dispersions of shear waves.
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Affiliation(s)
- Taras Bryk
- Institute for Condensed Matter Physics of the National Academy of Sciences of Ukraine, 1 Svientsitskii Street, UA-79011 Lviv, Ukraine
| | - Adrian Huerta
- Facultad de Física, Universidad Veracruzana, Circuito Gonzalo Aguirre Beltrán s/n Zona Universitaria Xalapa, Veracruz C.P. 91000, Mexico
| | - V Hordiichuk
- Institute for Condensed Matter Physics of the National Academy of Sciences of Ukraine, 1 Svientsitskii Street, UA-79011 Lviv, Ukraine
| | - A D Trokhymchuk
- Institute for Condensed Matter Physics of the National Academy of Sciences of Ukraine, 1 Svientsitskii Street, UA-79011 Lviv, Ukraine
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Bryk T, Wax JF. A search for manifestation of two types of collective excitations in dynamic structure of a liquid metal: Ab initio study of collective excitations in liquid Na. J Chem Phys 2017; 144:194501. [PMID: 27208952 DOI: 10.1063/1.4948709] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Using a combination of ab initio molecular dynamics and several fit models for dynamic structure of liquid metals, we explore an issue of possible manifestation of non-acoustic collective excitations in longitudinal dynamics having liquid Na as a case study. A model with two damped harmonic oscillators (DHOs) in time domain is used for analysis of the density-density time correlation functions. Another similar model with two propagating contributions and three lowest exact sum rules is considered, as well as an extended hydrodynamic model known as thermo-viscoelastic one which permits two types of propagating modes outside the hydrodynamic region to be used for comparison with ab initio obtained time correlation functions and calculations of dispersions of collective excitations. Our results do not support recent suggestions that, even in simple liquid metals, non-hydrodynamics transverse excitations contribute to the longitudinal collective dynamics and can be detected as a DHO-like spectral shape at their transverse frequency. We found that the thermo-viscoelastic dynamic model permits perfect description of the density-density and current-current time correlation functions of the liquid Na in a wide range of wave numbers, which implies that the origin of the non-hydrodynamic collective excitations contributing to longitudinal dynamics can be short-wavelength heat waves.
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Affiliation(s)
- Taras Bryk
- Institute for Condensed Matter Physics, National Academy of Sciences of Ukraine, 1 Svientsitskii Street, UA-79011 Lviv, Ukraine and Institute of Applied Mathematics and Fundamental Sciences, Lviv Polytechnic National University, UA-79013 Lviv, Ukraine
| | - J-F Wax
- Université de Lorraine, LCP-A2MC, EA4632, 1, boulevard Arago, 57078 Metz Cedex 3, France
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del Rio BG, González LE, González DJ. Ab initio study of several static and dynamic properties of bulk liquid Ni near melting. J Chem Phys 2017; 146:034501. [DOI: 10.1063/1.4973803] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Affiliation(s)
- B. G. del Rio
- Departamento de Física Teórica, Universidad de Valladolid, 47011 Valladolid, Spain
| | - L. E. González
- Departamento de Física Teórica, Universidad de Valladolid, 47011 Valladolid, Spain
| | - D. J. González
- Departamento de Física Teórica, Universidad de Valladolid, 47011 Valladolid, Spain
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del Rio BG, González LE, González DJ. Dynamic properties of liquid Ni revisited. EPJ WEB OF CONFERENCES 2017. [DOI: 10.1051/epjconf/201715102003] [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
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Wax JF, Bryk T. Analyzing the dynamic structure of liquid metals and alloys. EPJ WEB OF CONFERENCES 2017. [DOI: 10.1051/epjconf/201715102005] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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Bryk T, Demchuk T. Ab initio molecular dynamics study of collective dynamics in liquid Tl: Thermo-viscoelastic analysis. EPJ WEB OF CONFERENCES 2017. [DOI: 10.1051/epjconf/201715102001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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del Rio BG, González LE. Structure and dynamics of liquid Zn: an analysis of ab-initio simulations. EPJ WEB OF CONFERENCES 2017. [DOI: 10.1051/epjconf/201715103004] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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Marqués M, González LE, González DJ. Pressure-induced changes in structural and dynamic properties of liquid Fe close to the melting line. An ab initio study. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2016; 28:075101. [PMID: 26811899 DOI: 10.1088/0953-8984/28/7/075101] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
The static and dynamic properties of liquid Fe at high pressure and temperature have been studied using an ab initio molecular dynamics method. We have focused on four thermodynamic states at pressures of 27, 42, 50 and 58 GPa for which x-ray scattering data are available. The calculated static structure shows very good agreement with the available experimental data, including an asymmetric second peak which becomes more marked with increasing pressure. The dynamical structure reveals the existence of propagating density fluctuations and the associated dispersion relation has also been determined. The relaxation mechanisms for the density fluctuations have been analyzed in terms of a model with two decay channels (fast and slow, respectively). We found that the thermal relaxation proceeds along the slow decaying channel whereas the fast one is that of the viscoelastic relaxation. The possible coupling between longitudinal and transverse excitation modes has been investigated by looking at specific signatures in two wavevector regions: the first one is located around the position of the main peak of the structure factor, qp, as suggested by the recently reported appearance of high frequency transverse waves in liquid Li under high pressures; the second region is around qp/2, as suggested by the recent finding of transverse acoustic modes in inelastic x-ray scattering intensities of liquid Fe at ambient pressure. Finally, results are also reported for several transport coefficients.
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Affiliation(s)
- Miriam Marqués
- Departamento de Física Teórica, Universidad de Valladolid, Valladolid, Spain
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