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Roy AJ, Bergermann A, Bethkenhagen M, Redmer R. Mixture of hydrogen and methane under planetary interior conditions. Phys Chem Chem Phys 2024; 26:14374-14383. [PMID: 38712595 DOI: 10.1039/d4cp00058g] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/08/2024]
Abstract
We employ first-principles molecular dynamics simulations to provide equation-of-state data, pair distribution functions (PDFs), diffusion coefficients, and band gaps of a mixture of hydrogen and methane under planetary interior conditions as relevant for Uranus, Neptune, and similar icy exoplanets. We test the linear mixing approximation, which is fulfilled within a few percent for the chosen P-T conditions. Evaluation of the PDFs reveals that methane molecules dissociate into carbon clusters and free hydrogen atoms at temperatures greater than 3000 K. At high temperatures, the clusters are found to be short-lived. Furthermore, we calculate the electrical conductivity from which we derive the non-metal-to-metal transition region of the mixture. We also calculate the electrical conductivity along the P-T profile of Uranus [N. Nettelmann et al., Planet. Space Sci., 2013, 77, 143-151] and observe the transition of the mixture from a molecular to an atomic fluid as a function of the radius of the planet. The density and temperature ranges chosen in our study can be achieved using dynamic shock compression experiments and seek to aid such future experiments. Our work also provides a relevant data set for a better understanding of the interior, evolution, luminosity, and magnetic field of the ice giants in our solar system and beyond.
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Affiliation(s)
- Argha Jyoti Roy
- Institut für Physik, Universität Rostock, D-18051 Rostock, Germany
| | - Armin Bergermann
- Institut für Physik, Universität Rostock, D-18051 Rostock, Germany
| | - Mandy Bethkenhagen
- LULI, CNRS, CEA, Sorbonne Université, École Polytechnique - Institut Polytechnique de Paris, 91128 Palaiseau, France.
| | - Ronald Redmer
- Institut für Physik, Universität Rostock, D-18051 Rostock, Germany
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2
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Mi W, Luo K, Trickey SB, Pavanello M. Orbital-Free Density Functional Theory: An Attractive Electronic Structure Method for Large-Scale First-Principles Simulations. Chem Rev 2023; 123:12039-12104. [PMID: 37870767 DOI: 10.1021/acs.chemrev.2c00758] [Citation(s) in RCA: 8] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2023]
Abstract
Kohn-Sham Density Functional Theory (KSDFT) is the most widely used electronic structure method in chemistry, physics, and materials science, with thousands of calculations cited annually. This ubiquity is rooted in the favorable accuracy vs cost balance of KSDFT. Nonetheless, the ambitions and expectations of researchers for use of KSDFT in predictive simulations of large, complicated molecular systems are confronted with an intrinsic computational cost-scaling challenge. Particularly evident in the context of first-principles molecular dynamics, the challenge is the high cost-scaling associated with the computation of the Kohn-Sham orbitals. Orbital-free DFT (OFDFT), as the name suggests, circumvents entirely the explicit use of those orbitals. Without them, the structural and algorithmic complexity of KSDFT simplifies dramatically and near-linear scaling with system size irrespective of system state is achievable. Thus, much larger system sizes and longer simulation time scales (compared to conventional KSDFT) become accessible; hence, new chemical phenomena and new materials can be explored. In this review, we introduce the historical contexts of OFDFT, its theoretical basis, and the challenge of realizing its promise via approximate kinetic energy density functionals (KEDFs). We review recent progress on that challenge for an array of KEDFs, such as one-point, two-point, and machine-learnt, as well as some less explored forms. We emphasize use of exact constraints and the inevitability of design choices. Then, we survey the associated numerical techniques and implemented algorithms specific to OFDFT. We conclude with an illustrative sample of applications to showcase the power of OFDFT in materials science, chemistry, and physics.
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Affiliation(s)
- Wenhui Mi
- Key Laboratory of Material Simulation Methods & Software of Ministry of Education, College of Physics, Jilin University, Changchun 130012, PR China
- State Key Laboratory of Superhard Materials, Jilin University, Changchun 130012, PR China
- International Center of Future Science, Jilin University, Changchun 130012, PR China
| | - Kai Luo
- Department of Applied Physics, Nanjing University of Science and Technology, Nanjing 210094, PR China
| | - S B Trickey
- Quantum Theory Project, Department of Physics and Department of Chemistry, University of Florida, Gainesville, Florida 32611, United States
| | - Michele Pavanello
- Department of Physics and Department of Chemistry, Rutgers University, Newark, New Jersey 07102, United States
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3
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Ottoway CF, Rehn DA, Saumon D, Starrett CE. Effect of ionic disorder on the principal shock Hugoniot. Phys Rev E 2021; 104:055208. [PMID: 34942703 DOI: 10.1103/physreve.104.055208] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2021] [Accepted: 11/11/2021] [Indexed: 11/07/2022]
Abstract
The effect of ionic disorder on the principal Hugoniot is investigated using multiple scattering theory to very high pressure (Gbar). Calculations using molecular dynamics to simulate ionic disorder are compared to those with a fixed crystal lattice, for both carbon and aluminum. For the range of conditions considered here we find that ionic disorder has a relatively minor influence. It is most important at the onset of shell ionization and we find that, at higher pressures, the subtle effect of the ionic environment is overwhelmed by the larger number of ionized electrons with higher thermal energies.
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Affiliation(s)
- Crystal F Ottoway
- Los Alamos National Laboratory, P.O. Box 1663, Los Alamos, New Mexico 87545, USA
| | - Daniel A Rehn
- Los Alamos National Laboratory, P.O. Box 1663, Los Alamos, New Mexico 87545, USA
| | - Didier Saumon
- Los Alamos National Laboratory, P.O. Box 1663, Los Alamos, New Mexico 87545, USA
| | - C E Starrett
- Los Alamos National Laboratory, P.O. Box 1663, Los Alamos, New Mexico 87545, USA
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4
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Ovechkin AA, Loboda PA, Falkov AL, Sapozhnikov PA. Equation of state modeling with pseudoatom molecular dynamics. Phys Rev E 2021; 103:053206. [PMID: 34134221 DOI: 10.1103/physreve.103.053206] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2021] [Accepted: 04/28/2021] [Indexed: 11/07/2022]
Abstract
Using a modified version of the pseudoatom molecular-dynamics approach, the silicon and oxygen equations of state were generated and then employed to construct the equation of state of silicon dioxide. The results are supported by the close agreement with ab initio simulations of the silicon pressure and experimental shock Hugoniot of silicon dioxide. Ion thermal contributions to thermodynamic functions provided by the PAMD simulations are compared to their counterparts obtained with the one-component plasma and charged-hard-sphere approximations.
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Affiliation(s)
- A A Ovechkin
- Russian Federal Nuclear Center, Zababakhin All-Russian Research Institute of Technical Physics (RFNC-VNIITF), Snezhinsk, Chelyabinsk region 456770, Russia
| | - P A Loboda
- Russian Federal Nuclear Center, Zababakhin All-Russian Research Institute of Technical Physics (RFNC-VNIITF), Snezhinsk, Chelyabinsk region 456770, Russia.,National Research Nuclear University, Moscow Engineering Physics Institute (MEPhI), Moscow 115409, Russia
| | - A L Falkov
- Russian Federal Nuclear Center, Zababakhin All-Russian Research Institute of Technical Physics (RFNC-VNIITF), Snezhinsk, Chelyabinsk region 456770, Russia
| | - P A Sapozhnikov
- Russian Federal Nuclear Center, Zababakhin All-Russian Research Institute of Technical Physics (RFNC-VNIITF), Snezhinsk, Chelyabinsk region 456770, Russia
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5
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Starrett CE, Shaffer N. Multiple scattering theory for dense plasmas. Phys Rev E 2020; 102:043211. [PMID: 33212669 DOI: 10.1103/physreve.102.043211] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2020] [Accepted: 10/04/2020] [Indexed: 06/11/2023]
Abstract
Dense plasmas occur in stars, giant planets, and in inertial fusion experiments. Accurate modeling of the electronic structure of these plasmas allows for prediction of material properties that can in turn be used to simulate these astrophysical objects and terrestrial experiments. But modeling them remains a challenge. Here we explore the Korringa-Kohn-Rostoker Green's function (KKR-GF) method for this purpose. We find that it is able to predict equation of state in good agreement with other state-of-the-art methods, where they are accurate and viable. In addition, it is shown that the computational cost does not significantly change with temperature, in contrast with other approaches. Moreover, the method does not use pseudopotentials-core states are calculated self consistently. We conclude that KKR-GF is a very promising method for dense plasma simulation.
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Affiliation(s)
- C E Starrett
- Los Alamos National Laboratory, P.O. Box 1663, Los Alamos, New Mexico 87545, USA
| | - N Shaffer
- Los Alamos National Laboratory, P.O. Box 1663, Los Alamos, New Mexico 87545, USA
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7
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White AJ, Collins LA, Kress JD, Ticknor C, Clérouin J, Arnault P, Desbiens N. Correlation and transport properties for mixtures at constant pressure and temperature. Phys Rev E 2017; 95:063202. [PMID: 28709340 DOI: 10.1103/physreve.95.063202] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2017] [Indexed: 06/07/2023]
Abstract
Transport properties of mixtures of elements in the dense plasma regime play an important role in natural astrophysical and experimental systems, e.g., inertial confinement fusion. We present a series of orbital-free molecular dynamics simulations on dense plasma mixtures with comparison to a global pseudo ion in jellium model. Hydrogen is mixed with elements of increasingly high atomic number (lithium, carbon, aluminum, copper, and silver) at a fixed temperature of 100 eV and constant pressure set by pure hydrogen at 2g/cm^{3}, namely, 370 Mbars. We compute ionic transport coefficients, such as self-diffusion, mutual diffusion, and viscosity for various concentrations. Small concentrations of the heavy atoms significantly change the density of the plasma and decrease the transport coefficients. The structure of the mixture evidences a strong Coulomb coupling between heavy ions and the appearance of a broad correlation peak at short distances between hydrogen atoms. The concept of an effective one component plasma is used to quantify the overcorrelation of the light element induced by the admixture of a heavy element.
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Affiliation(s)
- Alexander J White
- Theoretical Division, Los Alamos National Laboratory, Los Alamos, New Mexico 87545, USA
| | - Lee A Collins
- Theoretical Division, Los Alamos National Laboratory, Los Alamos, New Mexico 87545, USA
| | - Joel D Kress
- Theoretical Division, Los Alamos National Laboratory, Los Alamos, New Mexico 87545, USA
| | - Christopher Ticknor
- Theoretical Division, Los Alamos National Laboratory, Los Alamos, New Mexico 87545, USA
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Colin-Lalu P, Recoules V, Salin G, Plisson T, Brambrink E, Vinci T, Bolis R, Huser G. Dissociation along the principal Hugoniot of the Laser Mégajoule ablator material. Phys Rev E 2016; 94:023204. [PMID: 27627404 DOI: 10.1103/physreve.94.023204] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2016] [Indexed: 06/06/2023]
Abstract
Glow discharge polymer hydrocarbon (GDP-CH) is used as the ablator material in inertial confinement fusion (ICF) capsules for the Laser Mégajoule and National Ignition Facility. Due to its fabrication process, GDP-CH chemical composition and structure differ from commercially available plastics and detailed knowledge of its properties in the warm dense matter regime is needed to achieve accurate design of ICF capsules. First-principles ab initio simulations of the GDP-CH principal Hugoniot up to 8 Mbar were performed using the quantum molecular dynamics (QMD) code abinit and showed that atomic bond dissociation has an effect on the compressibility. Results from these simulations are used to parametrize a quantum semiempirical model in order to generate a tabulated equation of state that includes dissociation. Hugoniot measurements obtained from an experiment conducted at the LULI2000 laser facility confirm QMD simulations as well as EOS modeling. We conclude by showing the EOS model influence on shock timing in a hydrodynamic simulation.
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Affiliation(s)
- P Colin-Lalu
- CEA, DAM, DIF, Bruyères-le-Châtel, F-91297 Arpajon, France
- Laboratoire pour l'Utilisation des Lasers Intenses (LULI) - CEA, CNRS, Ecole Polytechnique : Université Paris-Saclay, UPMC Université Paris 06 : Sorbonne Universités - F-91128 Palaiseau, France
| | - V Recoules
- CEA, DAM, DIF, Bruyères-le-Châtel, F-91297 Arpajon, France
| | - G Salin
- CEA, DAM, DIF, Bruyères-le-Châtel, F-91297 Arpajon, France
| | - T Plisson
- CEA, DAM, DIF, Bruyères-le-Châtel, F-91297 Arpajon, France
| | - E Brambrink
- Laboratoire pour l'Utilisation des Lasers Intenses (LULI) - CEA, CNRS, Ecole Polytechnique : Université Paris-Saclay, UPMC Université Paris 06 : Sorbonne Universités - F-91128 Palaiseau, France
| | - T Vinci
- Laboratoire pour l'Utilisation des Lasers Intenses (LULI) - CEA, CNRS, Ecole Polytechnique : Université Paris-Saclay, UPMC Université Paris 06 : Sorbonne Universités - F-91128 Palaiseau, France
| | - R Bolis
- Laboratoire pour l'Utilisation des Lasers Intenses (LULI) - CEA, CNRS, Ecole Polytechnique : Université Paris-Saclay, UPMC Université Paris 06 : Sorbonne Universités - F-91128 Palaiseau, France
| | - G Huser
- CEA, DAM, DIF, Bruyères-le-Châtel, F-91297 Arpajon, France
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9
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Ticknor C, Kress JD, Collins LA, Clérouin J, Arnault P, Decoster A. Transport properties of an asymmetric mixture in the dense plasma regime. Phys Rev E 2016; 93:063208. [PMID: 27415378 DOI: 10.1103/physreve.93.063208] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2016] [Indexed: 06/06/2023]
Abstract
We study how concentration changes ionic transport properties along isobars-isotherms for a mixture of hydrogen and silver, representative of turbulent layers relevant to inertial confinement fusion and astrophysics. Hydrogen will typically be fully ionized while silver will be only partially ionized but can have a large effective charge. This will lead to very different physical conditions for the H and Ag. Large first principles orbital free molecular dynamics simulations are performed and the resulting transport properties are analyzed. Comparisons are made with transport theory in the kinetic regime and in the coupled regime. The addition of a small amount of heavy element in a light material has a dramatic effect on viscosity and diffusion of the mixture. This effect is explained through kinetic theory as a manifestation of a crossover between classical diffusion and Lorentz diffusion.
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Affiliation(s)
- Christopher Ticknor
- Theoretical Division, Los Alamos National Laboratory, Los Alamos, New Mexico 87545, USA
| | - Joel D Kress
- Theoretical Division, Los Alamos National Laboratory, Los Alamos, New Mexico 87545, USA
| | - Lee A Collins
- Theoretical Division, Los Alamos National Laboratory, Los Alamos, New Mexico 87545, USA
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10
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Huser G, Recoules V, Ozaki N, Sano T, Sakawa Y, Salin G, Albertazzi B, Miyanishi K, Kodama R. Experimental and ab initio investigations of microscopic properties of laser-shocked Ge-doped ablator. PHYSICAL REVIEW. E, STATISTICAL, NONLINEAR, AND SOFT MATTER PHYSICS 2015; 92:063108. [PMID: 26764839 DOI: 10.1103/physreve.92.063108] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/18/2015] [Indexed: 06/05/2023]
Abstract
Plastic materials (CH) doped with mid-Z elements are used as ablators in inertial confinement fusion (ICF) capsules and in their surrogates. Hugoniot equation of state (EOS) and electronic properties of CH doped with germanium (at 2.5% and 13% dopant fractions) are investigated experimentally up to 7 Mbar using velocity and reflectivity measurements of shock fronts on the GEKKO laser at Osaka University. Reflectivity and temperature measurements were updated using a quartz standard. Shocked quartz reflectivity was measured at 532 and 1064 nm. Theoretical investigation of shock pressure and reflectivity was then carried out by ab initio simulations using the quantum molecular dynamics (QMD) code abinit and compared with tabulated average atom EOS models. We find that shock states calculated by QMD are in better agreement with experimental data than EOS models because of a more accurate description of ionic structure. We finally discuss electronic properties by comparing reflectivity data to a semiconductor gap closure model and to QMD simulations.
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Affiliation(s)
- G Huser
- CEA, DAM, DIF, Bruyères-le-Châtel, F-91297 Arpajon, France
| | - V Recoules
- CEA, DAM, DIF, Bruyères-le-Châtel, F-91297 Arpajon, France
| | - N Ozaki
- Graduate School of Engineering, Osaka University, Suita, Osaka 565-0871, Japan
- Photons Pioneers Center, Osaka University, Suita, Osaka 565-0871, Japan
| | - T Sano
- Institute of Laser Engineering, Osaka University, Suita, Osaka 565-0871, Japan
| | - Y Sakawa
- Institute of Laser Engineering, Osaka University, Suita, Osaka 565-0871, Japan
| | - G Salin
- CEA, DAM, DIF, Bruyères-le-Châtel, F-91297 Arpajon, France
| | - B Albertazzi
- Graduate School of Engineering, Osaka University, Suita, Osaka 565-0871, Japan
| | - K Miyanishi
- Graduate School of Engineering, Osaka University, Suita, Osaka 565-0871, Japan
- Photons Pioneers Center, Osaka University, Suita, Osaka 565-0871, Japan
| | - R Kodama
- Graduate School of Engineering, Osaka University, Suita, Osaka 565-0871, Japan
- Photons Pioneers Center, Osaka University, Suita, Osaka 565-0871, Japan
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Colin-Lalu P, Recoules V, Salin G, Huser G. Impact of oxygen on the 300-K isotherm of Laser Megajoule ablator using ab initio simulation. PHYSICAL REVIEW. E, STATISTICAL, NONLINEAR, AND SOFT MATTER PHYSICS 2015; 92:053104. [PMID: 26651799 DOI: 10.1103/physreve.92.053104] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/08/2015] [Indexed: 06/05/2023]
Abstract
The ablator material for inertial confinement fusion (ICF) capsules on the Laser Mégajoule is a glow-discharge polymer (GDP) plastic. Its equation of state (EOS) is of primary importance for the design of such capsules, since it has direct consequences on shock timing and is essential to mitigate hydrodynamic instabilities. Using ab initio molecular dynamics (AIMD), we have investigated the 300-K isotherm of amorphous CH(1.37)O(0.08) plastic, whose structure is close to GDP plastic. The 300-K isotherm, which is often used as a cold curve within tabular EOS, is an important contribution of the EOS in the multimegabar pressure range. AIMD results are compared to analytic models within tabular EOS, pointing out large discrepancies. In addition, we show that the effect of oxygen decreases 300-K isotherm pressure by 10%-15%. The implication of these observations is the ability to improve ICF target performance, which is essential to achieve fusion ignition.
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Affiliation(s)
- P Colin-Lalu
- CEA, DAM/DIF, Bruyères-le-Châtel, F-91297 Arpajon, France
- Laboratoire pour l'Utilisation des Lasers Intenses (LULI), École Polytechnique, F-91128 Palaiseau, France
| | - V Recoules
- CEA, DAM/DIF, Bruyères-le-Châtel, F-91297 Arpajon, France
| | - G Salin
- CEA, DAM/DIF, Bruyères-le-Châtel, F-91297 Arpajon, France
| | - G Huser
- CEA, DAM/DIF, Bruyères-le-Châtel, F-91297 Arpajon, France
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12
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Gill NM, Heinonen RA, Starrett CE, Saumon D. Ion-ion dynamic structure factor of warm dense mixtures. PHYSICAL REVIEW. E, STATISTICAL, NONLINEAR, AND SOFT MATTER PHYSICS 2015; 91:063109. [PMID: 26172810 DOI: 10.1103/physreve.91.063109] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/13/2015] [Indexed: 06/04/2023]
Abstract
The ion-ion dynamic structure factor of warm dense matter is determined using the recently developed pseudoatom molecular dynamics method [Starrett et al., Phys. Rev. E 91, 013104 (2015)]. The method uses density functional theory to determine ion-ion pair interaction potentials that have no free parameters. These potentials are used in classical molecular dynamics simulations. This constitutes a computationally efficient and realistic model of dense plasmas. Comparison with recently published simulations of the ion-ion dynamic structure factor and sound speed of warm dense aluminum finds good to reasonable agreement. Using this method, we make predictions of the ion-ion dynamical structure factor and sound speed of a warm dense mixture-equimolar carbon-hydrogen. This material is commonly used as an ablator in inertial confinement fusion capsules, and our results are amenable to direct experimental measurement.
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Affiliation(s)
- N M Gill
- 206 Allison Laboratory, Auburn University, Auburn, Alabama 36849, USA
- Los Alamos National Laboratory, P.O. Box 1663, Los Alamos, New Mexico 87545, USA
| | - R A Heinonen
- Los Alamos National Laboratory, P.O. Box 1663, Los Alamos, New Mexico 87545, USA
| | - C E Starrett
- Los Alamos National Laboratory, P.O. Box 1663, Los Alamos, New Mexico 87545, USA
| | - D Saumon
- Los Alamos National Laboratory, P.O. Box 1663, Los Alamos, New Mexico 87545, USA
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