1
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Okuda Y, Oka K, Kubota Y, Inada M, Kurita N, Ohta K, Hirose K. High-P-T impedance measurements using a laser-heated diamond anvil cell. THE REVIEW OF SCIENTIFIC INSTRUMENTS 2022; 93:105103. [PMID: 36319335 DOI: 10.1063/5.0097883] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/03/2022] [Accepted: 09/27/2022] [Indexed: 06/16/2023]
Abstract
The electrical conductivity (EC) of minerals found on Earth and throughout the solar system is a fundamental transport property that is used to understand various dynamical phenomena in planetary interiors. High-pressure and high-temperature (P-T) EC measurements are also an important tool for observing phase transitions. Impedance measurements can accurately measure the EC of a nonmetallic sample. In previous measurements under static conditions using a laser-heated diamond-anvil cell (LHDAC), only direct current resistance is measured, but this method overestimates the bulk sample resistance. Moreover, the previous methodology could only be applied to nontransparent samples in an LHDAC using infrared lasers, limiting the range of measurable composition. To the best of our knowledge, no in situ high-P-T EC measurements of transparent materials have been reported using LHDAC techniques. We developed a novel impedance measurement technique under high-P-T conditions in an LHDAC that applies to transparent samples. As a validation, we measured the EC of Mg0.9Fe0.1SiO3 bridgmanite up to 51 GPa and 2000 K and found that the results are consistent with those of previous studies. We also measured the EC values of sodium chloride to compare with those of previous studies, as well as those of cubic boron nitride and zirconia cement to quantify how well they insulate under high P-T conditions. This is the first report of the impedance and EC measurements of transparent minerals in an LHDAC, which allows the measurement of Fe-poor/-free materials, including the major constituents of the interiors of gas giants and icy planets, under extreme conditions.
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Affiliation(s)
- Yoshiyuki Okuda
- Department of Earth and Planetary Science, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, Japan
| | - Kenta Oka
- Department of Earth and Planetary Science, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, Japan
| | - Yusuke Kubota
- Department of Earth and Planetary Sciences, Tokyo Institute of Technology, Meguro, Tokyo 152-8551, Japan
| | - Mako Inada
- Department of Earth and Planetary Science, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, Japan
| | - Naoki Kurita
- Department of Earth and Planetary Science, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, Japan
| | - Kenji Ohta
- Department of Earth and Planetary Sciences, Tokyo Institute of Technology, Meguro, Tokyo 152-8551, Japan
| | - Kei Hirose
- Department of Earth and Planetary Science, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, Japan
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2
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Gleason AE, Rittman DR, Bolme CA, Galtier E, Lee HJ, Granados E, Ali S, Lazicki A, Swift D, Celliers P, Militzer B, Stanley S, Mao WL. Dynamic compression of water to conditions in ice giant interiors. Sci Rep 2022; 12:715. [PMID: 35027608 PMCID: PMC8758754 DOI: 10.1038/s41598-021-04687-6] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2021] [Accepted: 12/22/2021] [Indexed: 11/26/2022] Open
Abstract
Recent discoveries of water-rich Neptune-like exoplanets require a more detailed understanding of the phase diagram of H2O at pressure–temperature conditions relevant to their planetary interiors. The unusual non-dipolar magnetic fields of ice giant planets, produced by convecting liquid ionic water, are influenced by exotic high-pressure states of H2O—yet the structure of ice in this state is challenging to determine experimentally. Here we present X-ray diffraction evidence of a body-centered cubic (BCC) structured H2O ice at 200 GPa and ~ 5000 K, deemed ice XIX, using the X-ray Free Electron Laser of the Linac Coherent Light Source to probe the structure of the oxygen sub-lattice during dynamic compression. Although several cubic or orthorhombic structures have been predicted to be the stable structure at these conditions, we show this BCC ice phase is stable to multi-Mbar pressures and temperatures near the melt boundary. This suggests variable and increased electrical conductivity to greater depths in ice giant planets that may promote the generation of multipolar magnetic fields.
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Affiliation(s)
- A E Gleason
- Fundamental Physics Directorate, SLAC National Accelerator Laboratory, Menlo Park, CA, 94025, USA. .,Geological Sciences, Stanford University, Stanford, CA, 94305, USA.
| | - D R Rittman
- Geological Sciences, Stanford University, Stanford, CA, 94305, USA
| | - C A Bolme
- Shock and Detonation Physics, Los Alamos National Laboratory, Los Alamos, NM, 87545, USA
| | - E Galtier
- Linac Coherent Light Source, SLAC National Accelerator Laboratory, Menlo Park, CA, 94025, USA
| | - H J Lee
- Linac Coherent Light Source, SLAC National Accelerator Laboratory, Menlo Park, CA, 94025, USA
| | - E Granados
- Linac Coherent Light Source, SLAC National Accelerator Laboratory, Menlo Park, CA, 94025, USA
| | - S Ali
- Shock Physics, Lawrence Livermore National Laboratory, Livermore, CA, 94550, USA
| | - A Lazicki
- Shock Physics, Lawrence Livermore National Laboratory, Livermore, CA, 94550, USA
| | - D Swift
- Shock Physics, Lawrence Livermore National Laboratory, Livermore, CA, 94550, USA
| | - P Celliers
- Shock Physics, Lawrence Livermore National Laboratory, Livermore, CA, 94550, USA
| | - B Militzer
- Earth and Planetary Science, University of California, Berkeley, CA, 94720, USA
| | - S Stanley
- Earth and Planetary Sciences, Johns Hopkins University, Baltimore, MD, 21218, USA.,Applied Physics Lab, Johns Hopkins University, Laurel, MD, 20723, USA
| | - W L Mao
- Geological Sciences, Stanford University, Stanford, CA, 94305, USA
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3
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Ravasio A, Bethkenhagen M, Hernandez JA, Benuzzi-Mounaix A, Datchi F, French M, Guarguaglini M, Lefevre F, Ninet S, Redmer R, Vinci T. Metallization of Shock-Compressed Liquid Ammonia. PHYSICAL REVIEW LETTERS 2021; 126:025003. [PMID: 33512205 DOI: 10.1103/physrevlett.126.025003] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/18/2020] [Revised: 11/05/2020] [Accepted: 12/10/2020] [Indexed: 06/12/2023]
Abstract
Ammonia is predicted to be one of the major components in the depths of the ice giant planets Uranus and Neptune. Their dynamics, evolution, and interior structure are insufficiently understood and models rely imperatively on data for equation of state and transport properties. Despite its great significance, the experimentally accessed region of the ammonia phase diagram today is still very limited in pressure and temperature. Here we push the probed regime to unprecedented conditions, up to ∼350 GPa and ∼40 000 K. Along the Hugoniot, the temperature measured as a function of pressure shows a subtle change in slope at ∼7000 K and ∼90 GPa, in agreement with ab initio simulations we have performed. This feature coincides with the gradual transition from a molecular liquid to a plasma state. Additionally, we performed reflectivity measurements, providing the first experimental evidence of electronic conduction in high-pressure ammonia. Shock reflectance continuously rises with pressure above 50 GPa and reaches saturation values above 120 GPa. Corresponding electrical conductivity values are up to 1 order of magnitude higher than in water in the 100 GPa regime, with possible significant contributions of the predicted ammonia-rich layers to the generation of magnetic dynamos in ice giant interiors.
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Affiliation(s)
- A Ravasio
- LULI, CNRS, CEA, École Polytechnique-Institut Polytechnique de Paris, route de Saclay, 91128 Palaiseau cedex, France
| | - M Bethkenhagen
- École Normale Supérieure de Lyon, Université Lyon 1, Laboratoire de Géologie de Lyon, CNRS UMR 5276, 69364 Lyon Cedex 07, France
- Institut für Physik, Universität Rostock, 18051 Rostock, Germany
| | - J-A Hernandez
- LULI, CNRS, CEA, École Polytechnique-Institut Polytechnique de Paris, route de Saclay, 91128 Palaiseau cedex, France
- Centre for Earth Evolution and Dynamics, University of Oslo, N-0315 Oslo, Norway
| | - A Benuzzi-Mounaix
- LULI, CNRS, CEA, École Polytechnique-Institut Polytechnique de Paris, route de Saclay, 91128 Palaiseau cedex, France
| | - F Datchi
- Institut de Minéralogie, de Physique des Matériaux et de Cosmochimie (IMPMC), Sorbonne Université, CNRS UMR 7590, MNHN, 4 place Jussieu, F-75005 Paris, France
| | - M French
- Institut für Physik, Universität Rostock, 18051 Rostock, Germany
| | - M Guarguaglini
- LULI, CNRS, CEA, École Polytechnique-Institut Polytechnique de Paris, route de Saclay, 91128 Palaiseau cedex, France
| | - F Lefevre
- LULI, CNRS, CEA, École Polytechnique-Institut Polytechnique de Paris, route de Saclay, 91128 Palaiseau cedex, France
| | - S Ninet
- Institut de Minéralogie, de Physique des Matériaux et de Cosmochimie (IMPMC), Sorbonne Université, CNRS UMR 7590, MNHN, 4 place Jussieu, F-75005 Paris, France
| | - R Redmer
- Institut für Physik, Universität Rostock, 18051 Rostock, Germany
| | - T Vinci
- LULI, CNRS, CEA, École Polytechnique-Institut Polytechnique de Paris, route de Saclay, 91128 Palaiseau cedex, France
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4
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Guarguaglini M, Hernandez JA, Okuchi T, Barroso P, Benuzzi-Mounaix A, Bethkenhagen M, Bolis R, Brambrink E, French M, Fujimoto Y, Kodama R, Koenig M, Lefevre F, Miyanishi K, Ozaki N, Redmer R, Sano T, Umeda Y, Vinci T, Ravasio A. Laser-driven shock compression of "synthetic planetary mixtures" of water, ethanol, and ammonia. Sci Rep 2019; 9:10155. [PMID: 31300690 PMCID: PMC6626017 DOI: 10.1038/s41598-019-46561-6] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2018] [Accepted: 06/25/2019] [Indexed: 11/10/2022] Open
Abstract
Water, methane, and ammonia are commonly considered to be the key components of the interiors of Uranus and Neptune. Modelling the planets' internal structure, evolution, and dynamo heavily relies on the properties of the complex mixtures with uncertain exact composition in their deep interiors. Therefore, characterising icy mixtures with varying composition at planetary conditions of several hundred gigapascal and a few thousand Kelvin is crucial to improve our understanding of the ice giants. In this work, pure water, a water-ethanol mixture, and a water-ethanol-ammonia "synthetic planetary mixture" (SPM) have been compressed through laser-driven decaying shocks along their principal Hugoniot curves up to 270, 280, and 260 GPa, respectively. Measured temperatures spanned from 4000 to 25000 K, just above the coldest predicted adiabatic Uranus and Neptune profiles (3000-4000 K) but more similar to those predicted by more recent models including a thermal boundary layer (7000-14000 K). The experiments were performed at the GEKKO XII and LULI2000 laser facilities using standard optical diagnostics (Doppler velocimetry and optical pyrometry) to measure the thermodynamic state and the shock-front reflectivity at two different wavelengths. The results show that water and the mixtures undergo a similar compression path under single shock loading in agreement with Density Functional Theory Molecular Dynamics (DFT-MD) calculations using the Linear Mixing Approximation (LMA). On the contrary, their shock-front reflectivities behave differently by what concerns both the onset pressures and the saturation values, with possible impact on planetary dynamos.
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Affiliation(s)
- M Guarguaglini
- LULI, CNRS, CEA, École Polytechnique, Institut Polytechnique de Paris, route de Saclay, 91128, Palaiseau cedex, France. .,Sorbonne Université, Faculté des Sciences et Ingénierie, Laboratoire d'utilisation des lasers intenses (LULI), Campus Pierre et Marie Curie, place Jussieu, 75252, Paris cedex 05, France.
| | - J-A Hernandez
- LULI, CNRS, CEA, École Polytechnique, Institut Polytechnique de Paris, route de Saclay, 91128, Palaiseau cedex, France.,Sorbonne Université, Faculté des Sciences et Ingénierie, Laboratoire d'utilisation des lasers intenses (LULI), Campus Pierre et Marie Curie, place Jussieu, 75252, Paris cedex 05, France
| | - T Okuchi
- Institute for Planetary Materials, Okayama University, Misasa, Tottori, 682-0193, Japan
| | - P Barroso
- GEPI, Observatoire de Paris, PSL Université, CNRS, 77 avenue Denfert Rochereau, 75014, Paris, France
| | - A Benuzzi-Mounaix
- LULI, CNRS, CEA, École Polytechnique, Institut Polytechnique de Paris, route de Saclay, 91128, Palaiseau cedex, France.,Sorbonne Université, Faculté des Sciences et Ingénierie, Laboratoire d'utilisation des lasers intenses (LULI), Campus Pierre et Marie Curie, place Jussieu, 75252, Paris cedex 05, France
| | - M Bethkenhagen
- Universität Rostock, Institut für Physik, 18051, Rostock, Germany
| | - R Bolis
- LULI, CNRS, CEA, École Polytechnique, Institut Polytechnique de Paris, route de Saclay, 91128, Palaiseau cedex, France.,Sorbonne Université, Faculté des Sciences et Ingénierie, Laboratoire d'utilisation des lasers intenses (LULI), Campus Pierre et Marie Curie, place Jussieu, 75252, Paris cedex 05, France
| | - E Brambrink
- LULI, CNRS, CEA, École Polytechnique, Institut Polytechnique de Paris, route de Saclay, 91128, Palaiseau cedex, France.,Sorbonne Université, Faculté des Sciences et Ingénierie, Laboratoire d'utilisation des lasers intenses (LULI), Campus Pierre et Marie Curie, place Jussieu, 75252, Paris cedex 05, France
| | - M French
- Universität Rostock, Institut für Physik, 18051, Rostock, Germany
| | - Y Fujimoto
- Graduate School of Engineering, Osaka University, Suita, Osaka, 565-0871, Japan
| | - R Kodama
- Graduate School of Engineering, Osaka University, Suita, Osaka, 565-0871, Japan.,Open and Transdisciplinary Research Initiatives, Osaka University, Suita, Osaka, 565-0871, Japan.,Institute of Laser Engineering, Osaka University, Suita, Osaka, 565-0871, Japan
| | - M Koenig
- LULI, CNRS, CEA, École Polytechnique, Institut Polytechnique de Paris, route de Saclay, 91128, Palaiseau cedex, France.,Sorbonne Université, Faculté des Sciences et Ingénierie, Laboratoire d'utilisation des lasers intenses (LULI), Campus Pierre et Marie Curie, place Jussieu, 75252, Paris cedex 05, France.,Open and Transdisciplinary Research Initiatives, Osaka University, Suita, Osaka, 565-0871, Japan
| | - F Lefevre
- LULI, CNRS, CEA, École Polytechnique, Institut Polytechnique de Paris, route de Saclay, 91128, Palaiseau cedex, France
| | - K Miyanishi
- Institute of Laser Engineering, Osaka University, Suita, Osaka, 565-0871, Japan
| | - N Ozaki
- Graduate School of Engineering, Osaka University, Suita, Osaka, 565-0871, Japan.,Institute of Laser Engineering, Osaka University, Suita, Osaka, 565-0871, Japan
| | - R Redmer
- Universität Rostock, Institut für Physik, 18051, Rostock, Germany
| | - T Sano
- Institute of Laser Engineering, Osaka University, Suita, Osaka, 565-0871, Japan
| | - Y Umeda
- Graduate School of Engineering, Osaka University, Suita, Osaka, 565-0871, Japan
| | - T Vinci
- LULI, CNRS, CEA, École Polytechnique, Institut Polytechnique de Paris, route de Saclay, 91128, Palaiseau cedex, France.,Sorbonne Université, Faculté des Sciences et Ingénierie, Laboratoire d'utilisation des lasers intenses (LULI), Campus Pierre et Marie Curie, place Jussieu, 75252, Paris cedex 05, France
| | - A Ravasio
- LULI, CNRS, CEA, École Polytechnique, Institut Polytechnique de Paris, route de Saclay, 91128, Palaiseau cedex, France. .,Sorbonne Université, Faculté des Sciences et Ingénierie, Laboratoire d'utilisation des lasers intenses (LULI), Campus Pierre et Marie Curie, place Jussieu, 75252, Paris cedex 05, France.
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5
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6
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7
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8
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Meyer ER, Ticknor C, Bethkenhagen M, Hamel S, Redmer R, Kress JD, Collins LA. Bonding and structure in dense multi-component molecular mixtures. J Chem Phys 2015; 143:164513. [DOI: 10.1063/1.4934626] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Affiliation(s)
- Edmund R. Meyer
- 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
| | | | - Sebastien Hamel
- Lawrence Livermore National Laboratory, Livermore, California 94550, USA
| | - Ronald Redmer
- Institut für Physik, Universität Rostock, D-18501 Rostock, Germany
| | - 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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9
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The electrical conductivity of Al2O3 under shock-compression. Sci Rep 2015; 5:12823. [PMID: 26239369 PMCID: PMC4523845 DOI: 10.1038/srep12823] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2015] [Accepted: 07/13/2015] [Indexed: 11/08/2022] Open
Abstract
Sapphire (Al2O3) crystals are used below 100 GPa as anvils and windows in dynamic-compression experiments because of their transparency and high density. Above 100 GPa shock pressures, sapphire becomes opaque and electrically conducting because of shock-induced defects. Such effects prevent temperature and dc conductivity measurements of materials compressed quasi-isentropically. Opacities and electrical conductivities at ~100 GPa are non-equilibrium, rather than thermodynamic parameters. We have performed electronic structure calculations as a guide in predicting and interpreting shock experiments and possibly to discover a window up to ~200 GPa. Our calculations indicate shocked sapphire does not metallize by band overlap at ~300 GPa, as suggested previously by measured non-equilibrium data. Shock-compressed Al2O3 melts to a metallic liquid at ~500 GPa and 10,000 K and its conductivity increases rapidly to ~2000 Ω(-1)cm(-1) at ~900 GPa. At these high shock temperatures and pressures sapphire is in thermal equilibrium. Calculated conductivity of Al2O3 is similar to those measured for metallic fluid H, N, O, Rb, and Cs. Despite different materials, pressures and temperatures, and compression techniques, both experimental and theoretical, conductivities of all these poor metals reach a common end state typical of strong-scattering disordered materials.
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11
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Bethkenhagen M, French M, Redmer R. Equation of state and phase diagram of ammonia at high pressures from ab initio simulations. J Chem Phys 2014; 138:234504. [PMID: 23802968 DOI: 10.1063/1.4810883] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
Abstract
We present an equation of state as well as a phase diagram of ammonia at high pressures and high temperatures derived from ab initio molecular dynamics simulations. The predicted phases of ammonia are characterized by analyzing diffusion coefficients and structural properties. Both the phase diagram and the subsequently computed Hugoniot curves are compared to experimental results. Furthermore, we discuss two methods that allow us to take into account nuclear quantum effects, which are of considerable importance in molecular fluids. Our data cover pressures up to 330 GPa and a temperature range from 500 K to 10,000 K. This regime is of great interest for interior models of the giant planets Uranus and Neptune, which contain, besides water and methane, significant amounts of ammonia.
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12
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Ross PW, Tran V, Chau R. High bandwidth differential amplifier for shock experiments. THE REVIEW OF SCIENTIFIC INSTRUMENTS 2012; 83:10D718. [PMID: 23126892 DOI: 10.1063/1.4732858] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
We developed a high bandwidth differential amplifier for gas gun shock experiments of low-resistance metals. The circuit has a bandwidth up to 1 GHz, and is capable of measuring signals of ≤1.5 V with a common mode rejection of 250 V. Conductivity measurements of gas gun targets are measured by flowing high currents through the targets. The voltage is measured across the target using a technique similar to a four-point probe. Because of the design of the current source and load, the target voltage is ∼250 V relative to ground. Since the expected voltage change in the target is <1 V, the differential amplifier must have a large common mode rejection. Various amplifying designs are shown, although the increased amplification decreases bandwidth. Bench tests show that the amplifier can withstand significant common mode dc voltage and measure 10 ns, and 50 mV signals.
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Affiliation(s)
- P W Ross
- National Security Technologies, LLC, Livermore, California 94550, USA.
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13
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Ninet S, Datchi F, Saitta AM. Proton disorder and superionicity in hot dense ammonia ice. PHYSICAL REVIEW LETTERS 2012; 108:165702. [PMID: 22680735 DOI: 10.1103/physrevlett.108.165702] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/16/2012] [Indexed: 06/01/2023]
Abstract
We report the experimental discovery of a new phase of ammonia ice, stable at pressures above 57 GPa and temperatures above 700 K. The combination of our experimental results and ab initio molecular dynamics simulations reveal that this new phase is a superionic conductor, characterized by a large proton diffusion coefficient (1.0×10(-4) cm(2)/s at 70 GPa, 850 K). Proton diffusion occurs via a Grotthuss-like mechanism, at a surprisingly lower temperature than in water ice. This may have implications for the onset of superionicity in the molecular ice mixtures present in Jovian planets. Our simulations further suggest that the anisotropic proton hopping along different H bonds in the molecular solid may explain the formation of the recently predicted ionic phase at low temperatures.
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Affiliation(s)
- S Ninet
- Institut de Minéralogie et de Physique des Milieux Condensés, Université Pierre et Marie Curie-Paris 6, CNRS UMR 7590, Paris, France
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14
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Chau R, Hamel S, Nellis WJ. Chemical processes in the deep interior of Uranus. Nat Commun 2011; 2:203. [DOI: 10.1038/ncomms1198] [Citation(s) in RCA: 62] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2010] [Accepted: 01/19/2011] [Indexed: 11/09/2022] Open
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15
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Lee MS, Scandolo S. Mixtures of planetary ices at extreme conditions. Nat Commun 2011; 2:185. [PMID: 21304514 DOI: 10.1038/ncomms1184] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2010] [Accepted: 01/11/2011] [Indexed: 11/09/2022] Open
Abstract
The interiors of Neptune and Uranus are believed to be primarily composed of a fluid mixture of methane and water. The mixture is subjected to pressures up to several hundred gigapascal, causing the ionization of water. Laboratory and simulation studies so far have focused on the properties of the individual components. Here we show, using first-principle molecular dynamic simulations, that the properties of the mixed fluid are qualitatively different with respect to those of its components at the same conditions. We observe a pressure-induced softening of the methane-water intermolecular repulsion that points to an enhancement of mixing under extreme conditions. Ionized water causes the progressive ionization of methane and the mixture becomes electronically conductive at milder conditions than pure water, indicating that the planetary magnetic field of Uranus and Neptune may originate at shallower depths than currently assumed.
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Affiliation(s)
- Mal-Soon Lee
- The Abdus Salam International Centre for Theoretical Physics, Trieste I-34151, Italy
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16
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Ninet S, Datchi F. High pressure-high temperature phase diagram of ammonia. J Chem Phys 2008; 128:154508. [PMID: 18433236 DOI: 10.1063/1.2903491] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
The high pressure (P)-high temperature (T) phase diagram of solid ammonia has been investigated using diamond anvil cell and resistive heating techniques. The III-IV transition line has been determined up to 20 GPa and 500 K both on compression and decompression paths. No discontinuity is observed at the expected location for the III-IV-V triple point. The melting line has been determined by visual observations of the fluid-solid equilibrium up to 9 GPa and 900 K. The experimental data are well fitted by a Simon-Glatzel equation in the covered P-T range. These transition lines and their extrapolations are compared to the reported ab initio calculations.
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Affiliation(s)
- S Ninet
- Institut de Minéralogie et de Physique des Milieux Condensés, Département Physique des Milieux Denses, CNRS UMR 7590, Université Pierre et Marie Curie-Paris VI, Paris Cedex 05, France.
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Batani D, Stabile H, Canova F, Koenig M, Benuzzi A, Nishimura H, Ochi Y, Ullschmied J, Skala J, Kralikova B, Pfeifer M, Mocek T, Präg A. High-pressure behavior of carbon by laser-generated shocks. RUSSIAN JOURNAL OF PHYSICAL CHEMISTRY A 2007. [DOI: 10.1134/s0036024407090026] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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18
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The Reactivity of Energetic Materials at Extreme Conditions. REVIEWS IN COMPUTATIONAL CHEMISTRY 2007. [DOI: 10.1002/9780470189078.ch4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register]
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19
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Lee KKM, Benedetti LR, Jeanloz R, Celliers PM, Eggert JH, Hicks DG, Moon SJ, Mackinnon A, Da Silva LB, Bradley DK, Unites W, Collins GW, Henry E, Koenig M, Benuzzi-Mounaix A, Pasley J, Neely D. Laser-driven shock experiments on precompressed water: Implications for “icy” giant planets. J Chem Phys 2006; 125:014701. [PMID: 16863318 DOI: 10.1063/1.2207618] [Citation(s) in RCA: 68] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
Laser-driven shock compression of samples precompressed to 1 GPa produces high-pressure-temperature conditions inducing two significant changes in the optical properties of water: the onset of opacity followed by enhanced reflectivity in the initially transparent water. The onset of reflectivity at infrared wavelengths can be interpreted as a semiconductor<-->electronic conductor transition in water, and is found at pressures above approximately 130 GPa for single-shocked samples precompressed to 1 GPa. Our results indicate that conductivity in the deep interior of "icy" giant planets is greater than realized previously because of an additional contribution from electrons.
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Affiliation(s)
- Kanani K M Lee
- Department of Earth & Planetary Science, University of California-Berkeley, Berkeley, California 94720-4767, USA
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20
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Goldman N, Fried LE, Kuo IFW, Mundy CJ. Bonding in the superionic phase of water. PHYSICAL REVIEW LETTERS 2005; 94:217801. [PMID: 16090349 DOI: 10.1103/physrevlett.94.217801] [Citation(s) in RCA: 45] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/02/2004] [Indexed: 05/03/2023]
Abstract
The predicted superionic phase of water is investigated via ab initio molecular dynamics at densities of 2.0--3.0 g/cc (34-115 GPa) along the 2000 K isotherm. We find that extremely rapid (superionic) diffusion of protons occurs in a fluid phase at pressures between 34 and 58 GPa. A transition to a stable body-centered cubic O lattice with superionic proton conductivity is observed between 70 and 75 GPa, a much higher pressure than suggested in prior work. We find that all molecular species at pressures greater than 75 GPa are too short lived to be classified as bound states. Up to 95 GPa, we find a solid superionic phase characterized by covalent O-H bonding. Above 95 GPa, a transient network phase is found characterized by symmetric O-H hydrogen bonding with nearly 50% covalent character. In addition, we describe a metastable superionic phase with quenched O disorder.
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Affiliation(s)
- Nir Goldman
- Lawrence Livermore National Laboratory, P.O. Box 808, Livermore, California 94550, USA
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21
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Batani D, Strati F, Stabile H, Tomasini M, Lucchini G, Ravasio A, Koenig M, Benuzzi-Mounaix A, Nishimura H, Ochi Y, Ullschmied J, Skala J, Kralikova B, Pfeifer M, Kadlec C, Mocek T, Präg A, Hall T, Milani P, Barborini E, Piseri P. Hugoniot data for carbon at megabar pressures. PHYSICAL REVIEW LETTERS 2004; 92:065503. [PMID: 14995252 DOI: 10.1103/physrevlett.92.065503] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/02/2003] [Indexed: 05/24/2023]
Abstract
We present an experimental point for the carbon equation of state (EOS) at megabar pressures, obtained by laser-driven shock waves. The rear side emissivity of "two-materials two-steps" targets (Al-C) was recorded with space and time resolution and, by applying the impedance mismatch method, allowed a direct determination of relative EOS points. Experiments were performed at the PALS and LULI laboratories using carbon samples with two different values of initial density, in order to explore a wider region of the phase diagram. Previously unreached pressures were obtained. The results are compared with previous experiments and with available theoretical models and seem to show a high compressibility of carbon at megabar pressures.
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Affiliation(s)
- D Batani
- Dipartimento di Fisica G. Occhialini, Università degli Studi di Milano Bicocca and INFM, Piazza della Scienza 3, 20126 Milan, Italy
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22
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Viecelli JA, Glosli JN. Carbon cluster coagulation and fragmentation kinetics in shocked hydrocarbons. J Chem Phys 2002. [DOI: 10.1063/1.1522395] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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23
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Katoh E, Yamawaki H, Fujihisa H, Sakashita M, Aoki K. Protonic diffusion in high-pressure ice VII. Science 2002; 295:1264-6. [PMID: 11847334 DOI: 10.1126/science.1067746] [Citation(s) in RCA: 41] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Abstract
Near ambient pressures, molecular diffusion dominates protonic diffusion in ice. Theoretical studies have predicted that protonic diffusion will dominate at high pressures in ice. We measured the protonic diffusion coefficient for the highest temperature molecular phase of ice VII at 400 kelvin over its entire stable pressure region. The values ranged from 10(-17) to 10(-15) square meters per second at pressures of 10 to 63 gigapascals. The diffusion coefficients extrapolated to high temperatures close to the ice VII melting curve were less by a factor of 10(2) to 10(3) than a superionic criterion of approximately 10(-8) square meters per second, at which protons would diffuse freely.
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Affiliation(s)
- Eriko Katoh
- National Institute of Advanced Industrial Science and Technology, Tsukuba Central 5, Tsukuba 305-8565, Ibaraki, Japan
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24
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Abstract
Recent high-pressure studies reveal a wealth of new information about the behavior of molecular materials subjected to pressures well into the multimegabar range (several hundred gigapascal), corresponding to compressions in excess of an order of magnitude. Under such conditions, bonding patterns established for molecular systems near ambient conditions change dramatically, causing profound effects on numerous physical and chemical properties and leading to the formation of new classes of materials. Representative systems are examined to illustrate key phenomena, including the evolution of structure and bonding with compression; pressure-induced phase transitions and chemical reactions; pressure-tuning of vibrational dynamics, quantum effects, and excited electronic states; and novel states of electronic and magnetic order. Examples are taken from simple elemental molecules (e.g. homonuclear diatomics), simple heteronuclear species, hydrogen-bonded systems (including H2O), simple molecular mixtures, and selected larger, more complex molecules. There are many implications that span the sciences.
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Affiliation(s)
- R J Hemley
- Geophysical Laboratory and Center for High Pressure Research, Carnegie Institution of Washington, Washington, DC 20015, USA.
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25
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Cavazzoni C, Chiarotti GL, Scandolo S, Tosatti E, Bernasconi M, Parrinello M. Superionic and metallic states of water and ammonia at giant planet conditions. Science 1999; 283:44-6. [PMID: 9872734 DOI: 10.1126/science.283.5398.44] [Citation(s) in RCA: 387] [Impact Index Per Article: 15.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Abstract
The phase diagrams of water and ammonia were determined by constant pressure ab initio molecular dynamic simulations at pressures (30 to 300 gigapascal) and temperatures (300 to 7000 kelvin) of relevance for the middle ice layers of the giant planets Neptune and Uranus. Along the planetary isentrope water and ammonia behave as fully dissociated ionic, electronically insulating fluid phases, which turn metallic at temperatures exceeding 7000 kelvin for water and 5500 kelvin for ammonia. At lower temperatures, the phase diagrams of water and ammonia exhibit a superionic solid phase between the solid and the ionic liquid. These simulations improve our understanding of the properties of the middle ice layers of Neptune and Uranus.
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Affiliation(s)
- C Cavazzoni
- Istituto Nazionale per la Fisica della Materia (INFM) and International School for Advanced Studies (SISSA), Via Beirut 4, I-34014 Trieste, Italy
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