Molecular Dissociation in Hot, Dense Hydrogen

Magro, W. R.; Ceperley, David M.; Pierleoni, Carlo; Bernu, B.

doi:10.1103/physrevlett.76.1240

Cited by 228 publications

(175 citation statements)

References 14 publications

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“…(4)). In support of these chemical models, the physically based PIMC calculations [66] also give rather similar results. On the other hand the TB simulations give a gradual transition to a more "monatomic" phase.…”

Section: Scenario 3: Metal-insulator Transition Induced By Structusupporting

confidence: 63%

“…Possibilities include the crossing or merging of the lines, as well as their termination in one or two critical points. Recent theoretical predictions of a Plasma Phase Transition (PPT) [66,68] are schematically depicted as well. Also depicted in the figure is the Simon equation for the melting line, and the orientationally disordered (I) and ordered phases (II) and (III) found in the solid [52].…”

Section: Fig 4 Schematic Phase Diagrammentioning

confidence: 99%

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Metallization of fluid hydrogen

Nellis

Louis

Ashcroft

1998

Philosophical Transactions of the Royal Society of London. Seri

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The electrical resistivity of liquid hydrogen has been measured at the high dynamic pressures, densities and temperatures that can be achieved with a reverberating shock wave. The resulting data are most naturally interpreted in terms of a continuous transition from a semiconducting to a metallic, largely diatomic fluid, the latter at 140 GPa, (ninefold compression) and 3000 K. While the fluid at these conditions resembles common liquid metals by the scale of its resistivity of 500 micro-ohm-cm, it differs by retaining a strong pairing character, and the precise mechanism by which a metallic state might be attained is still a matter of debate. Some evident possibilities include (i) physics of a largely one-body character, such as a band-overlap transition, (ii) physics of a strongcoupling or many-body character,such as a Mott-Hubbard transition, and (iii) processes in which structural changes are paramount.

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Section: Scenario 3: Metal-insulator Transition Induced By Structusupporting

confidence: 63%

Section: Fig 4 Schematic Phase Diagrammentioning

confidence: 99%

Metallization of fluid hydrogen

Nellis

Louis

Ashcroft

1998

Philosophical Transactions of the Royal Society of London. Seri

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“…Fermionic PIMC simulations have been applied to study hydrogen [31][32][33][34][35][36][37][38][39], helium [40,41], hydrogen-helium mixtures [42], and one-component plasmas [43,44], and most recently to simulate carbon and water plasmas [14]. In PIMC simulations, electrons and nuclei are treated equally as Feynman paths in a stochastic framework for solving the full, finite-temperature, quantum many-body problem.…”

Section: B Pimc Calculationsmentioning

confidence: 99%

Multiphase equation of state for carbon addressing high pressures and temperatures

et al. 2014

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We present a 5-phase equation of state for elemental carbon which addresses a wide range of density and temperature conditions: 3g/cc < ρ < 20g/cc, 0 K < T < ∞. The phases considered are diamond, BC8, simple cubic, simple hexagonal, and the liquid/plasma state. The solid phase free energies are constrained by density functional theory (DFT) calculations. Vibrational contributions to the free energy of each solid phase are treated within the quasiharmonic framework. The liquid free energy model is constrained by fitting to a combination of DFT molecular dynamics performed over the range 10 000 K < T < 100 000 K, and path integral quantum Monte Carlo calculations for T > 100 000 K (both for ρ between 3 and 12 g/cc, with select higher-ρ DFT calculations as well). The liquid free energy model includes an atom-in-jellium approach to account for the effects of ionization due to temperature and pressure in the plasma state, and an ion-thermal model which includes the approach to the ideal gas limit. The precise manner in which the ideal gas limit is reached is greatly constrained by both the highest-temperature DFT data and the path integral data, forcing us to discard an ion-thermal model we had used previously in favor of a new one. Predictions are made for the principal Hugoniot and the room-temperature isotherm, and comparisons are made to recent experimental results.

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“…The transition is complicated by the prediction that pressure ionization is commensurate with molecular dissociation. Various theoretical predictions about how the EOS could be affect& by the phase transition[26-321, and evem whether the transition was of first order [29,33], had been made since this regime is also important for the description of the atmospheres of Jovian planets and low-mass stars that are 90% hydrogen (the E0 § of all of the hydrogen isotopes are similar; there is only a scale factor in density between them). Gas gun experiments had been done [34] but the highest Hugoniot pressure datum was about 200 kbar, not high enough to exhibit the predicted effects.…”

Section: Indirectly-driven Huponiotsmentioning

confidence: 99%

“…The measurements were made with streak radiography using x-rays from a laser-heated backlighter; an image is shown in (b). c) Absolute beryllium Hugoniot data [24] compared with SESAME EQS table Hugoniot [25] and nuclear impedance match data[ 14,151. gas gun data (triangles) [34] compared with theoretical results: SESAME (solid) [25,26]; molecular dynamics (dot-dash) [31]; Monte Carlo (dash-double-dot) [29]; ACTEX (chaindash) [32]; Saumon and Chabrier (dashes) [28]; and linear mixing (dots) [35]. …”

Section: Sn1987a Remnant Collision Exuerimentsmentioning

confidence: 99%

Laboratory measurements of materials in extreme conditions: the use of high energy radiation sources for high pressure studies

Cauble¹,

Remington²,

Campbell³

1999

International Journal of Impact Engineering

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High energy lasers can be used to study material conditions that are appropriate fort inertial confinement fusion: that is, materials at high densities, temperatures, and pressures. Pulsed power devices can offer similar opportunities. The National Ignition Facility (NIP) will be a high energy multi-beam laser designed to achieve the thermonuclear ignition of a mm-scale DT-fried target in the laboratory. At the same time, NE will provide the physics community with a unique tool for the study of high energy density matter at states unreachable by any other laboratory technique. Here we describe how these lasers and pulsed power tools can contribute to investigations of high energy density matter in the areas of material properties and equations of state, extend present laboratory shock techniques such as high-speed jets to new regimes, and allow study of extreme conditions found in astrophysical phenomenaThe purpose of this article is to introduce and describe the kinds of high energy density experiments that are now being done with high energy radiation sources --lasers and pulsed power devices --on present-day facilities and to indicate where these investigations might proceed with larger facilities either on the drawing board or under construction. Both pulsed power and laser facilities have been funded predominantly for research i,n inertial confinement fusion (KF) or, in the case ofpulsed power% as high flux, short wavelength x-ray sources. The idea that they could be used to investigate specific areas of high energy density physics took some time to germinate, The growth of physics-specific experiments on lasers and pulsed power has been driven largely by the need for high energy density information in the absence of nuclear testing.Although the use of high energy lasers for studies of, e.g., material properties at extremely high pressure or high-Mach-number hydrodynamic flow, is recent --less than 10 years, the use of pulsed power machines for such experiments is even newer. Since there is a base of laser experiments on facilities like Nova at Lawrence Livermore National Laboratory (LLNL), the bulk of this article will discuss those experiments. Pulsed power facilities like Z at Sandia National Laboratories (SNL) can and will perform measurements similar to those described below. Extensions of Nova experiments to next generation lasers, like the National Ignition Facility (to be bui1.t at LLNL) can be made. The next generation pulsed power machine, designated X-l, may be built at SNL in the next century.Lasers and pulsed power devices can produce high energy radiation sources but can be seen as somewhat complementary. The most energetic laser for the past 15 years has been Nova[ I], although the B&EGA laser[Z!] at the University of Rochester is now equivalent. Nova is a tenbeam laser that can produce about 1.00 kJ of l-pm-wavelength laser light. This long wavelength,

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Molecular Dissociation in Hot, Dense Hydrogen

Cited by 228 publications

References 14 publications

Metallization of fluid hydrogen

Metallization of fluid hydrogen

Multiphase equation of state for carbon addressing high pressures and temperatures

Laboratory measurements of materials in extreme conditions: the use of high energy radiation sources for high pressure studies

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