1
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Hadad RE, Roy A, Rabani E, Redmer R, Baer R. Stochastic density functional theory combined with Langevin dynamics for warm dense matter. Phys Rev E 2024; 109:065304. [PMID: 39020867 DOI: 10.1103/physreve.109.065304] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2024] [Accepted: 05/17/2024] [Indexed: 07/19/2024]
Abstract
This study overviews and extends a recently developed stochastic finite-temperature Kohn-Sham density functional theory to study warm dense matter using Langevin dynamics, specifically under periodic boundary conditions. The method's algorithmic complexity exhibits nearly linear scaling with system size and is inversely proportional to the temperature. Additionally, a linear-scaling stochastic approach is introduced to assess the Kubo-Greenwood conductivity, demonstrating exceptional stability for dc conductivity. Utilizing the developed tools, we investigate the equation of state, radial distribution, and electronic conductivity of hydrogen at a temperature of 30 000 K. As for the radial distribution functions, we reveal a transition of hydrogen from gaslike to liquidlike behavior as its density exceeds 4g/cm^{3}. As for the electronic conductivity as a function of the density, we identified a remarkable isosbestic point at frequencies around 7 eV, which may be an additional signature of a gas-liquid transition in hydrogen at 30 000 K.
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Affiliation(s)
| | | | - Eran Rabani
- Department of Chemistry, University of California, Berkeley, California 94720, USA; Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA; and The Raymond and Beverly Sackler Center of Computational Molecular and Materials Science, Tel Aviv University, Tel Aviv 69978, Israel
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2
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Xie H, Li ZH, Wang H, Zhang L, Wang L. Deep Variational Free Energy Approach to Dense Hydrogen. PHYSICAL REVIEW LETTERS 2023; 131:126501. [PMID: 37802941 DOI: 10.1103/physrevlett.131.126501] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/19/2022] [Revised: 08/01/2023] [Accepted: 08/14/2023] [Indexed: 10/08/2023]
Abstract
We developed a deep generative model-based variational free energy approach to the equations of state of dense hydrogen. We employ a normalizing flow network to model the proton Boltzmann distribution and a fermionic neural network to model the electron wave function at given proton positions. By jointly optimizing the two neural networks we reached a comparable variational free energy to the previous coupled electron-ion Monte Carlo calculation. The predicted equation of state of dense hydrogen under planetary conditions is denser than the findings of ab initio molecular dynamics calculation and empirical chemical model. Moreover, direct access to the entropy and free energy of dense hydrogen opens new opportunities in planetary modeling and high-pressure physics research.
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Affiliation(s)
- Hao Xie
- Beijing National Laboratory for Condensed Matter Physics and Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
- School of Physical Sciences, University of Chinese Academy of Sciences, Beijing 100190, China
| | - Zi-Hang Li
- Beijing National Laboratory for Condensed Matter Physics and Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
- School of Physical Sciences, University of Chinese Academy of Sciences, Beijing 100190, China
| | - Han Wang
- Laboratory of Computational Physics, Institute of Applied Physics and Computational Mathematics, Fenghao East Road 2, Beijing 100094, China
| | - Linfeng Zhang
- DP Technology, Beijing 100080, China
- AI for Science Institute, Beijing 100080, China
| | - Lei Wang
- Beijing National Laboratory for Condensed Matter Physics and Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
- Songshan Lake Materials Laboratory, Dongguan, Guangdong 523808, China
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3
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Robinson RS, Tiwari P, McMahon JM. Pseudo pair potential between protons in dense hydrogen from first principles. Mol Phys 2022. [DOI: 10.1080/00268976.2022.2104178] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/16/2022]
Affiliation(s)
- Robbie S. Robinson
- Department of Physics and Astronomy, Washington State University, Pullman, WA, USA
| | - Praveer Tiwari
- Department of Physics and Astronomy, Washington State University, Pullman, WA, USA
| | - Jeffrey M. McMahon
- Department of Physics and Astronomy, Washington State University, Pullman, WA, USA
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4
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Lavrinenko Y, Levashov PR, Minakov DV, Morozov IV, Valuev IA. Equilibrium properties of warm dense deuterium calculated by the wave packet molecular dynamics and density functional theory method. Phys Rev E 2021; 104:045304. [PMID: 34781451 DOI: 10.1103/physreve.104.045304] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2021] [Accepted: 09/13/2021] [Indexed: 11/07/2022]
Abstract
A joint simulation method based on the wave packet molecular dynamics and density functional theory (WPMD-DFT) is applied to study warm dense deuterium (nonideal deuterium plasmas). This method was developed recently as an extension of the wave packet molecular dynamics (WPMD) in which the equations of motion are solved simultaneously for classical ions and semiclassical electrons represented as Gaussian wave packets. Compared to the classical molecular dynamics and WPMD simulations, the method of WPMD-DFT provides a more accurate representation of quantum effects such as electron-ion coupling and electron degeneracy. It allows studying nonadiabatic dynamics of electrons and ions in equilibrium and nonequilibrium states while being more accurate and efficient at high densities than WPMD and classical molecular dynamics. In the paper, we discuss particular features of the method such as special boundary conditions and the procedure of isentrope calculation as well as the results obtained by WPMD-DFT for the shock-compressed deuterium. The compression isentrope and principal Hugoniot curves obtained by WPMD-DFT are compared with available experimental data and other simulation approaches to validate the method. It opens up a possibility of further application of the method to study nonequilibrium states and relaxation processes.
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Affiliation(s)
- Yaroslav Lavrinenko
- Joint Institute for High Temperatures of Russian Academy of Sciences, Moscow 125412, Russia.,Moscow Institute of Physics and Technology, Dolgoprudny 141701, Russia
| | - Pavel R Levashov
- Joint Institute for High Temperatures of Russian Academy of Sciences, Moscow 125412, Russia.,Moscow Institute of Physics and Technology, Dolgoprudny 141701, Russia
| | - Dmitry V Minakov
- Joint Institute for High Temperatures of Russian Academy of Sciences, Moscow 125412, Russia.,Moscow Institute of Physics and Technology, Dolgoprudny 141701, Russia
| | - Igor V Morozov
- Joint Institute for High Temperatures of Russian Academy of Sciences, Moscow 125412, Russia.,Moscow Institute of Physics and Technology, Dolgoprudny 141701, Russia
| | - Ilya A Valuev
- Joint Institute for High Temperatures of Russian Academy of Sciences, Moscow 125412, Russia
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5
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van de Bund S, Wiebe H, Ackland GJ. Isotope Quantum Effects in the Metallization Transition in Liquid Hydrogen. PHYSICAL REVIEW LETTERS 2021; 126:225701. [PMID: 34152180 DOI: 10.1103/physrevlett.126.225701] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/13/2020] [Revised: 11/12/2020] [Accepted: 04/21/2021] [Indexed: 06/13/2023]
Abstract
Quantum effects in condensed matter normally only occur at low temperatures. Here we show a large quantum effect in high-pressure liquid hydrogen at thousands of Kelvins. We show that the metallization transition in hydrogen is subject to a very large isotope effect, occurring hundreds of degrees lower than the equivalent transition in deuterium. We examined this using path integral molecular dynamics simulations which identify a liquid-liquid transition involving atomization, metallization, and changes in viscosity, specific heat, and compressibility. The difference between H_{2} and D_{2} is a quantum mechanical effect that can be associated with the larger zero-point energy in H_{2} weakening the covalent bond. Our results mean that experimental results on deuterium must be corrected before they are relevant to understanding hydrogen at planetary conditions.
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Affiliation(s)
- Sebastiaan van de Bund
- School of Physics & Astronomy, The University of Edinburgh, Edinburgh EH9 3FD, United Kingdom
| | - Heather Wiebe
- School of Physics & Astronomy, The University of Edinburgh, Edinburgh EH9 3FD, United Kingdom
| | - Graeme J Ackland
- School of Physics & Astronomy, The University of Edinburgh, Edinburgh EH9 3FD, United Kingdom
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6
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Tian C, Liu F, Yuan H, Chen H, Gan Y. First-principles equation of state of liquid hydrogen and dissociative transition. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2021; 33:015401. [PMID: 32932242 DOI: 10.1088/1361-648x/abb896] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
The properties of dense hot hydrogen, in particular the phase transition between the molecular insulating and atomic conductive states, are important in the fields of astrophysics and high-pressure physics. Previous ab initio calculations suggested the metallization in liquid hydrogen, accompanied by dissociation, is a first-order phase transition and ends at a critical point in temperature range between 1500 and 2000 K and pressure close to 100 GPa. Using density functional theoretical molecular dynamics simulations, we report a first-principles equation of state of hydrogen that covers dissociation transition conditions at densities ranging from 0.20 to 1.00 g/cc and temperatures of 600-9000 K. Our results clearly indicate that a drop in pressure and a sharp structural change still occur as the system transforms from a diatomic to monoatomic phase at temperatures above 2000 K, and support the first-order phase transition in liquid hydrogen would end in the temperature about 4500 K.
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Affiliation(s)
- Chunling Tian
- School of Physical Science and Technology, Southwest University, Chongqing 400715, People's Republic of China
| | - Fusheng Liu
- Institute of High Pressure Physics, Southwest Jiaotong University, Chengdu 610031, People's Republic of China
| | - Hongkuan Yuan
- School of Physical Science and Technology, Southwest University, Chongqing 400715, People's Republic of China
| | - Hong Chen
- School of Physical Science and Technology, Southwest University, Chongqing 400715, People's Republic of China
| | - Yundan Gan
- Xi'an institute of modern chemistry, Xian 710000, People's Republic of China
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7
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Tian C, Liu F, Yuan H, Chen H, Kuan A. First-order liquid-liquid phase transition in compressed hydrogen and critical point. J Chem Phys 2019; 150:204114. [PMID: 31153203 DOI: 10.1063/1.5096400] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
One of the fundamental problems relating to the properties of hydrogen is that of insulator-metal transition. Recent theoretical and experimental studies show that the metallization in liquid hydrogen could be a first-order phase transition and involve molecular to atomic transition. However, the location of the critical point is still an unresolved question. Earlier studies reported the critical point at a temperature of 1500-2000 K, but recent experimental observations on diamond-anvil cells show that the discontinuous transition still persists at temperatures well above 2000 K. We have carried out a detailed study on the liquid-liquid phase transition in dense hydrogen by uisng ab initio molecular dynamics simulations and found new evidence for the abrupt metallization between weakly dissociated and strongly dissociated fluid phases at temperatures as high as 3000 and 4000 K. Also, the predicted phase boundary is in excellent agreement with the recent experiments. Our results suggest that this first-order transition in liquid hydrogen likely ends in a critical point around 4000 K, which is significantly higher than the previous theoretical predictions.
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Affiliation(s)
- Chunling Tian
- School of Physical Science and Technology, Southwest University, Chongqing 400715, China
| | - Fusheng Liu
- Institute of High Pressure Physics, Southwest Jiaotong University, Chengdu 610031, China
| | - Hongkuan Yuan
- School of Physical Science and Technology, Southwest University, Chongqing 400715, China
| | - Hong Chen
- School of Physical Science and Technology, Southwest University, Chongqing 400715, China
| | - Anlong Kuan
- School of Physical Science and Technology, Southwest University, Chongqing 400715, China
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9
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10
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Mazzola G, Helled R, Sorella S. Phase Diagram of Hydrogen and a Hydrogen-Helium Mixture at Planetary Conditions by Quantum Monte Carlo Simulations. PHYSICAL REVIEW LETTERS 2018; 120:025701. [PMID: 29376719 DOI: 10.1103/physrevlett.120.025701] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/02/2017] [Indexed: 06/07/2023]
Abstract
Understanding planetary interiors is directly linked to our ability of simulating exotic quantum mechanical systems such as hydrogen (H) and hydrogen-helium (H-He) mixtures at high pressures and temperatures. Equation of state (EOS) tables based on density functional theory are commonly used by planetary scientists, although this method allows only for a qualitative description of the phase diagram. Here we report quantum Monte Carlo (QMC) molecular dynamics simulations of pure H and H-He mixture. We calculate the first QMC EOS at 6000 K for a H-He mixture of a protosolar composition, and show the crucial influence of He on the H metallization pressure. Our results can be used to calibrate other EOS calculations and are very timely given the accurate determination of Jupiter's gravitational field from the NASA Juno mission and the effort to determine its structure.
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Affiliation(s)
| | - Ravit Helled
- Institute for Computational Science, Center for Theoretical Astrophysics and Cosmology, University of Zurich, 8057 Zurich, Switzerland
| | - Sandro Sorella
- International School for Advanced Studies (SISSA) and INFM Democritos National Simulation Center, via Bonomea 265, 34136 Trieste, Italy
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11
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Geng HY, Wu Q, Sun Y. Prediction of a Mobile Solid State in Dense Hydrogen under High Pressures. J Phys Chem Lett 2017; 8:223-228. [PMID: 27973848 DOI: 10.1021/acs.jpclett.6b02453] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
Solid rigidity and liquid-scale mobility are thought to be incompatible in elemental substances. One cannot have an elemental solid that is long-range positionally ordered wherein the atoms flow like in a liquid simultaneously. The only exception might be the hypothetical supersolid state of 4He. In this work, we demonstrate that such exotic state could exist even in the classical regime. Using ab initio molecular dynamics (AIMD) and ab initio path integral molecular dynamics (AI-PIMD), a novel state of dense hydrogen that simultaneously has both long-range spatial ordering and liquid-scale atomic mobility is discovered at 1 to 1.5 TPa (1 TPa ≈ 10 000 000 atmospheric pressures). The features distinct from a normal solid and liquid are carefully characterized, and the stability and melting behavior are investigated. Extensive AI-PIMD simulations further revealed that this state might be (meta-)stable even at ultralow temperatures, suggesting an emerging candidate for an alternative type of supersolid state in dense metallic hydrogen.
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Affiliation(s)
- Hua Y Geng
- National Key Laboratory of Shock Wave and Detonation Physics, Institute of Fluid Physics, CAEP ; P.O. Box 919-102 Mianyang, Sichuan P. R. China , 621900
| | - Q Wu
- National Key Laboratory of Shock Wave and Detonation Physics, Institute of Fluid Physics, CAEP ; P.O. Box 919-102 Mianyang, Sichuan P. R. China , 621900
| | - Y Sun
- National Key Laboratory of Shock Wave and Detonation Physics, Institute of Fluid Physics, CAEP ; P.O. Box 919-102 Mianyang, Sichuan P. R. China , 621900
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12
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Danel JF, Kazandjian L, Piron R. Equation of state of warm dense deuterium and its isotopes from density-functional theory molecular dynamics. Phys Rev E 2016; 93:043210. [PMID: 27176421 DOI: 10.1103/physreve.93.043210] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2015] [Indexed: 06/05/2023]
Abstract
Of the two approaches of density-functional theory molecular dynamics, quantum molecular dynamics is limited at high temperature by computational cost whereas orbital-free molecular dynamics, based on an approximation of the kinetic electronic free energy, can be implemented in this domain. In the case of deuterium, it is shown how orbital-free molecular dynamics can be regarded as the limit of quantum molecular dynamics at high temperature for the calculation of the equation of state. To this end, accurate quantum molecular dynamics calculations are performed up to 20 eV at mass densities as low as 0.5g/cm^{3} and up to 10 eV at mass densities as low as 0.2g/cm^{3}. As a result, the limitation in temperature so far attributed to quantum molecular dynamics is overcome and an approach combining quantum and orbital-free molecular dynamics is used to construct an equation of state of deuterium. The thermodynamic domain addressed is that of the fluid phase above 1 eV and 0.2g/cm^{3}. Both pressure and internal energy are calculated as functions of temperature and mass density, and various exchange-correlation contributions are compared. The generalized gradient approximation of the exchange-correlation functional, corrected to approximately include the influence of temperature, is retained and the results obtained are compared to other approaches and to experimental shock data; in parts of the thermodynamic domain addressed, these results significantly differ from those obtained in other first-principles investigations which themselves disagree. The equations of state of hydrogen and tritium above 1 eV and above, respectively, 0.1g/cm^{3} and 0.3g/cm^{3}, can be simply obtained by mass density scaling from the results found for deuterium. This ab initio approach allows one to consistently cover a very large domain of temperature on the domain of mass density outlined above.
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Affiliation(s)
- J-F Danel
- CEA, DAM, DIF, F-91297 Arpajon, France
| | | | - R Piron
- CEA, DAM, DIF, F-91297 Arpajon, France
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13
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Dornheim T, Schoof T, Groth S, Filinov A, Bonitz M. Permutation blocking path integral Monte Carlo approach to the uniform electron gas at finite temperature. J Chem Phys 2015; 143:204101. [DOI: 10.1063/1.4936145] [Citation(s) in RCA: 54] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Affiliation(s)
- Tobias Dornheim
- Institut für Theoretische Physik und Astrophysik, Christian-Albrechts-Universität, Leibnizstrasse 15, Kiel D-24098, Germany
| | - Tim Schoof
- Institut für Theoretische Physik und Astrophysik, Christian-Albrechts-Universität, Leibnizstrasse 15, Kiel D-24098, Germany
| | - Simon Groth
- Institut für Theoretische Physik und Astrophysik, Christian-Albrechts-Universität, Leibnizstrasse 15, Kiel D-24098, Germany
| | - Alexey Filinov
- Institut für Theoretische Physik und Astrophysik, Christian-Albrechts-Universität, Leibnizstrasse 15, Kiel D-24098, Germany
- Joint Institute for High Temperatures RAS, Izhorskaya Str. 13, 125412 Moscow, Russia
| | - Michael Bonitz
- Institut für Theoretische Physik und Astrophysik, Christian-Albrechts-Universität, Leibnizstrasse 15, Kiel D-24098, Germany
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14
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McMinis J, Clay RC, Lee D, Morales MA. Molecular to atomic phase transition in hydrogen under high pressure. PHYSICAL REVIEW LETTERS 2015; 114:105305. [PMID: 25815944 DOI: 10.1103/physrevlett.114.105305] [Citation(s) in RCA: 56] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/05/2014] [Indexed: 06/04/2023]
Abstract
The metallization of high-pressure hydrogen, together with the associated molecular to atomic transition, is one of the most important problems in the field of high-pressure physics. It is also currently a matter of intense debate due to the existence of conflicting experimental reports on the observation of metallic hydrogen on a diamond-anvil cell. Theoretical calculations have typically relied on a mean-field description of electronic correlation through density functional theory, a theory with well-known limitations in the description of metal-insulator transitions. In fact, the predictions of the pressure-driven dissociation of molecules in high-pressure hydrogen by density functional theory is strongly affected by the chosen exchange-correlation functional. In this Letter, we use quantum Monte Carlo calculations to study the molecular to atomic transition in hydrogen. We obtain a transition pressure of 447(3) GPa, in excellent agreement with the best experimental estimate of the transition 450 GPa based on an extrapolation to zero band gap from experimental measurements. Additionally, we find that C2/c is stable almost up to the molecular to atomic transition, in contrast to previous density functional theory (DFT) and DFT+quantum Monte Carlo studies which predict large stability regimes for intermediary molecular phases.
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Affiliation(s)
- Jeremy McMinis
- Lawrence Livermore National Laboratory, Livermore, California 94550, USA
| | - Raymond C Clay
- Lawrence Livermore National Laboratory, Livermore, California 94550, USA
- University of Illinois, Urbana, Illinois 61821, USA
| | - Donghwa Lee
- Lawrence Livermore National Laboratory, Livermore, California 94550, USA
| | - Miguel A Morales
- Lawrence Livermore National Laboratory, Livermore, California 94550, USA
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15
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Quan WL, Chen QF, Fu ZJ, Sun XW, Zheng J, Gu YJ. Equations of state, transport properties, and compositions of argon plasma: combination of self-consistent fluid variation theory and linear response theory. PHYSICAL REVIEW. E, STATISTICAL, NONLINEAR, AND SOFT MATTER PHYSICS 2015; 91:023106. [PMID: 25768617 DOI: 10.1103/physreve.91.023106] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/14/2014] [Indexed: 06/04/2023]
Abstract
A consistent theoretical model that can be applied in a wide range of densities and temperatures is necessary for understanding the variation of a material's properties during compression and heating. Taking argon as an example, we show that the combination of self-consistent fluid variational theory and linear response theory is a promising route for studying warm dense matter. Following this route, the compositions, equations of state, and transport properties of argon plasma are calculated in a wide range of densities (0.001-20 g/cm(3)) and temperatures (5-100 kK). The obtained equations of state and electrical conductivities are found in good agreement with available experimental data. The plasma phase transition of argon is observed at temperatures below 30 kK and density about 2-6g/cm(3). The minimum density for the metallization of argon is found to be about 5.8 g/cm(3), occurring at 30-40 kK. The effects of many-particle correlations and dynamic screening on the electrical conductivity are also discussed through the effective potentials.
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Affiliation(s)
- W L Quan
- National key Laboratory of Shock Wave and Detonation Physics, Institute of Fluid Physics, CAEP, Mianyang 621900, China
- School of Mathematics and Physics, Lanzhou Jiaotong University, Lanzhou 730070, China
| | - Q F Chen
- National key Laboratory of Shock Wave and Detonation Physics, Institute of Fluid Physics, CAEP, Mianyang 621900, China
| | - Z J Fu
- National key Laboratory of Shock Wave and Detonation Physics, Institute of Fluid Physics, CAEP, Mianyang 621900, China
| | - X W Sun
- School of Mathematics and Physics, Lanzhou Jiaotong University, Lanzhou 730070, China
| | - J Zheng
- National key Laboratory of Shock Wave and Detonation Physics, Institute of Fluid Physics, CAEP, Mianyang 621900, China
| | - Y J Gu
- National key Laboratory of Shock Wave and Detonation Physics, Institute of Fluid Physics, CAEP, Mianyang 621900, China
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Becker A, Lorenzen W, Fortney JJ, Nettelmann N, Schöttler M, Redmer R. AB INITIO EQUATIONS OF STATE FOR HYDROGEN (H-REOS.3) AND HELIUM (He-REOS.3) AND THEIR IMPLICATIONS FOR THE INTERIOR OF BROWN DWARFS. ACTA ACUST UNITED AC 2014. [DOI: 10.1088/0067-0049/215/2/21] [Citation(s) in RCA: 92] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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17
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Luo Y, Zen A, Sorella S. Ab initio molecular dynamics with noisy forces: Validating the quantum Monte Carlo approach with benchmark calculations of molecular vibrational properties. J Chem Phys 2014; 141:194112. [DOI: 10.1063/1.4901430] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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18
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Morales MA, Gergely JR, McMinis J, McMahon JM, Kim J, Ceperley DM. Quantum Monte Carlo Benchmark of Exchange-Correlation Functionals for Bulk Water. J Chem Theory Comput 2014; 10:2355-62. [DOI: 10.1021/ct500129p] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Miguel A. Morales
- Lawrence Livermore
National Laboratory, Livermore, California 94550, United States
| | - John R. Gergely
- Department
of Physics, University of Illinois at Urbana−Champaign, Urbana, Illinois 61801 United States
| | - Jeremy McMinis
- Lawrence Livermore
National Laboratory, Livermore, California 94550, United States
| | - Jeffrey M. McMahon
- Department
of Physics, University of Illinois at Urbana−Champaign, Urbana, Illinois 61801 United States
| | - Jeongnim Kim
- Material Science
and Technology Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, United States and
- Computer Science
and Mathematics Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, United States
| | - David M. Ceperley
- Department
of Physics, University of Illinois at Urbana−Champaign, Urbana, Illinois 61801 United States
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19
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Reboredo FA, Kim J. Generalizing the self-healing diffusion Monte Carlo approach to finite temperature: A path for the optimization of low-energy many-body bases. J Chem Phys 2014; 140:074103. [DOI: 10.1063/1.4861222] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
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20
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Schoof T, Groth S, Bonitz M. Introduction to Configuration Path Integral Monte Carlo. COMPLEX PLASMAS 2014. [DOI: 10.1007/978-3-319-05437-7_5] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
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21
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Brown E, Morales MA, Pierleoni C, Ceperley D. Quantum Monte Carlo Techniques and Applications for Warm Dense Matter. LECTURE NOTES IN COMPUTATIONAL SCIENCE AND ENGINEERING 2014. [DOI: 10.1007/978-3-319-04912-0_5] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
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22
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23
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Gohr S, Grimme S, Söhnel T, Paulus B, Schwerdtfeger P. Pressure dependent stability and structure of carbon dioxide—A density functional study including long-range corrections. J Chem Phys 2013; 139:174501. [DOI: 10.1063/1.4826929] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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24
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Morales MA, McMahon JM, Pierleoni C, Ceperley DM. Nuclear quantum effects and nonlocal exchange-correlation functionals applied to liquid hydrogen at high pressure. PHYSICAL REVIEW LETTERS 2013; 110:065702. [PMID: 23432276 DOI: 10.1103/physrevlett.110.065702] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/16/2012] [Indexed: 06/01/2023]
Abstract
Using first-principles molecular dynamics, we study the influence of nuclear quantum effects (NQEs) and nonlocal exchange-correlation density functionals (DFs) near molecular dissociation in liquid hydrogen. NQEs strongly influence intramolecular properties, such as bond stability, and are thus an essential part of the dissociation process. Moreover, by including DFs that account for either the self-interaction error or dispersion interactions, we find a much better description of molecular dissociation and metallization than previous studies based on classical protons and/or local or semilocal DFs. We obtain excellent agreement with experimentally measured optical properties along Hugoniot curves for precompressed states, and while we still find a first-order liquid-liquid transition at low temperatures, transition pressures are increased by more than 100 GPa.
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Affiliation(s)
- Miguel A Morales
- Lawrence Livermore National Laboratory, Livermore, California 94550, USA.
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Liberatore E, Morales MA, Ceperley DM, Pierleoni C. Free energy methods in coupled electron ion Monte Carlo. Mol Phys 2011. [DOI: 10.1080/00268976.2011.624992] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/16/2022]
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Caillabet L, Canaud B, Salin G, Mazevet S, Loubeyre P. Change in inertial confinement fusion implosions upon using an ab initio multiphase DT equation of state. PHYSICAL REVIEW LETTERS 2011; 107:115004. [PMID: 22026681 DOI: 10.1103/physrevlett.107.115004] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/17/2011] [Indexed: 05/31/2023]
Abstract
Improving the description of the equation of state (EOS) of deuterium-tritium (DT) has recently been shown to change significantly the gain of an inertial confinement fusion target [S. X. Hu et al., Phys. Rev. Lett. 104, 235003 (2010)]. Here we use an advanced multiphase EOS, based on ab initio calculations, to perform a full optimization of the laser pulse shape with hydrodynamic simulations starting from 19 K in DT ice. The thermonuclear gain is shown to be a robust estimate over possible uncertainties of the EOS. Two different target designs are discussed, for shock ignition and self-ignition. In the first case, the areal density and thermonuclear energy can be recovered by slightly increasing the laser energy. In the second case, a lower in-flight adiabat is needed, leading to a significant delay (3 ns) in the shock timing of the implosion.
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Evidence for a first-order liquid-liquid transition in high-pressure hydrogen from ab initio simulations. Proc Natl Acad Sci U S A 2010; 107:12799-803. [PMID: 20566888 DOI: 10.1073/pnas.1007309107] [Citation(s) in RCA: 98] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Using quantum simulation techniques based on either density functional theory or quantum Monte Carlo, we find clear evidence of a first-order transition in liquid hydrogen, between a low conductivity molecular state and a high conductivity atomic state. Using the temperature dependence of the discontinuity in the electronic conductivity, we estimate the critical point of the transition at temperatures near 2,000 K and pressures near 120 GPa. Furthermore, we have determined the melting curve of molecular hydrogen up to pressures of 200 GPa, finding a reentrant melting line. The melting line crosses the metalization line at 700 K and 220 GPa using density functional energetics and at 550 K and 290 GPa using quantum Monte Carlo energetics.
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