Bulletin of the American Physical Society
APS March Meeting 2017
Volume 62, Number 4
Monday–Friday, March 13–17, 2017; New Orleans, Louisiana
Session C2: Materials in Extremes IFocus
|
Hide Abstracts |
Sponsoring Units: DCOMP DMP SHOCK Chair: Ivan Oleynik, University of South Florida Room: 261 |
Monday, March 13, 2017 2:30PM - 3:06PM |
C2.00001: Novel approaches to ab-initio studies of materials at extreme conditions of high pressure and high temperature Invited Speaker: Sergei Simak Theoretical description of thermodynamics, phase equilibria, and phase transitions in materials at high temperatures and pressures should include proper treatment of thermal motions of atoms. We show how this can be done in an accurate way within the modeling based on first-principles molecular dynamics. Our novel approach is illustrated by the examples ranging from elemental metals to superionic conductors. [Preview Abstract] |
Monday, March 13, 2017 3:06PM - 3:18PM |
C2.00002: Polymerization of sodium-doped liquid nitrogen under pressure Stanimir Bonev, Marc Cormier Using first-principles theory, we have investigated the possibility of reducing the polymerization pressure of N through impurity doping. A description of structural and electronic properties leading to an understanding of the effect of Na-doping on the polymerization phase transition will be presented. We show that it develops in three distinct stages, commences at much lower pressure compared to the pure N system even with a small Na concentration, and there are qualitative changes in its evolution beyond a certain Na concentration. [Preview Abstract] |
Monday, March 13, 2017 3:18PM - 3:30PM |
C2.00003: The liquid-liquid phase transition in dense hydrogen David Ceperley, Carlo Pierleoni, Markus Holzmann, Miguel Morales The phase diagram of high pressure hydrogen is of great interest for fundamental research. A first-order phase transition in the fluid phase between a molecular insulating fluid and a monoatomic metallic fluid has been long anticipated. Recent experiments reported contrasting results about the location of the transition and theoretical results are very uncertain. We report highly accurate coupled electron-ion quantum Monte Carlo calculations of this transition, finding results that lie between the two experimental predictions, close to that measured in diamond anvil cell experiments but at 25-30 GPa higher pressure. The transition along an isotherm is signaled by a discontinuity in the specific volume, a sudden dissociation of the molecules, a jump in electrical conductivity and loss of electron localization. For details see Proc. Nat. Acad. Sc. 113, 4953–4957, 2016. [Preview Abstract] |
Monday, March 13, 2017 3:30PM - 3:42PM |
C2.00004: Symmetrization of Dense D$_{\mathrm{2}}$S under Pressure Sakun Duwal, Choong-Shik Yoo Solid H$_{\mathrm{2}}$S, like H$_{\mathrm{2}}$O, is a typical hydrogen-bonded molecular crystal; yet, unlike H$_{\mathrm{2}}$O, the stability and chemistry of dense H$_{\mathrm{2}}$S is substantially more complex and less understood. We have investigated the phase diagram of D$_{\mathrm{2}}$S to 70 GPa in diamond anvil cells using confocal micro-Raman spectroscopy. The results show the formation of ``polymeric'' D$_{\mathrm{2}}$S (phase V) at 30 GPa at 300 K, analogous to "symmetric" ice-X. The formation of proton symmetrized D$_{\mathrm{2}}$S is evident by the characteristic single Raman peak at 460 cm$^{\mathrm{-1}}$ for symmetric bending/stretching vibrational mode, analogous to that of ice X at 730 cm$^{\mathrm{-1\thinspace }}$at 76 GPa. At low temperatures, we also found the proton-ordering transitions to phase IV' and VI, both of which transform to phase V at 40 GPa at 100 K. The present results indicate higher chemical stability of D$_{\mathrm{2}}$S in contrast to the previously suggested decomposition of H$_{\mathrm{2}}$S above 30 GPa. [Preview Abstract] |
Monday, March 13, 2017 3:42PM - 3:54PM |
C2.00005: Emergence of superconductivity in doped H$_2$O ice at high pressure Jose A. Flores-Livas, Antonio Sanna, Arkady Davydov, Stefan Goedecker, Miguel A.L. Marques We investigate the possibility of achieving high-temperature superconductivity in hydrides under pressure by inducing metallization of otherwise insulating phases through doping, a path previously used to render standard semiconductors superconducting at ambient pressure. Following this idea, we study H$_{\rm 2}$O, one of the most abundant and well-studied substances, we identify nitrogen as the most likely and promising substitution/dopant. We show that for realistic levels of doping of a few percent, the phase X of ice becomes superconducting with a critical temperature of about 60~K at 150~GPa. In view of the vast number of hydrides that are strongly covalent bonded, but that remain insulating up to rather large pressures, our results open a series of new possibilities in the quest for novel high-temperature superconductors. [Preview Abstract] |
Monday, March 13, 2017 3:54PM - 4:06PM |
C2.00006: Pressure-Induced Intercalation of Solid Hydrogen into Graphite Jinhyuk Lim, Minseob Kim, Young-Jay Ryu, Choong-Shik Yoo Carbon-based nanomaterials such as graphene, carbon nanotubes and fullerenes have attracted many researchers as the promising candidates for hydrogen storages. However, the attempts have not been successful for graphite, presumably because of a limited space between graphitic layers. Here, we present pressure-induced intercalation of solid hydrogen into graphite, as evident in Raman spectroscopy and x-ray diffraction. Upon the solidification of hydrogen above 5.5 GPa, we found that hydrogen vibron becomes asymmetrically distorted and develops two distinct side bands which are greatly blue-shifted. Furthermore, synchrotron x-ray diffraction data also show an abrupt increase of the c-axis of graphite at 5.5 GPa, underscoring the intercalation of solid hydrogen into the graphite. These results have significant implication for development of 2D hetero-layered materials at high pressures, as well as hydrogen storage in graphite at low temperature and ambient pressure. [Preview Abstract] |
Monday, March 13, 2017 4:06PM - 4:18PM |
C2.00007: Pressure Effect on Hydrogen Tunneling and Vibrational Spectrum in $\alpha$-Mn Alexander Kolesnikov, Andrey Podlesnyak, Ravil Sadykov, Vladimir Antonov, Michail Kuzovnikov, Georg Ehlers, Garrett Granroth The pressure effect on the tunneling mode and vibrational spectra of hydrogen in $\alpha$-MnH$_{0.07}$ has been studied by inelastic neutron scattering. Applying hydrostatic pressure of up to 30 kbar is shown to shift both the hydrogen optical modes and the tunneling peak to higher energies. First-principles calculations show that the potential for hydrogen in $\alpha$-Mn becomes overall steeper with increasing pressure. At the same time, the barrier height and its extent in the direction of tunneling decrease and the calculations predict significant changes of the dynamics of hydrogen in $\alpha$-Mn at 100 kbar, when the estimated tunneling splitting of the hydrogen ground state exceeds the barrier height. Acknowledgments: Research at ORNL SNS was supported by the Sci. User Facilities Division, Office BES, US DOE, and was sponsored by the LDRD Program of ORNL, managed by UT-Battelle, LLC, for the US DOE. It used resources of the Nat. Energy Res. Sci. Comp. Center, which is supported by the Office of Sci. US DOE under Contract No. DE-AC02-05CH11231. A support by a Grant of the Program on Elementary Particle Physics, Fundamental Nuclear Physics and Nuclear Techn. RAS is also acknowledged. [Preview Abstract] |
Monday, March 13, 2017 4:18PM - 4:30PM |
C2.00008: Spectroscopic and structural study of LLM-172 under pressure Gustav Borstad, Jennifer Ciezak-Jenkins The properties of energetic materials have been investigated to permit the synthesis and scale-up of novel energetic materials possessing low sensitivity without sacrificing performance. To this end, there have been considerable efforts expended on the preparation of molecular crystals featuring unsaturated heterocycles with energetic functional groups such as LLM-105 and LLM-172 (BNFF-1)\footnote[1]{A. DeHope, P. F. Pagoria, and D. Parrish, ``New polynitro alkylamino furazans" (No. LLNL-CONF-624954), Lawrence Livermore National Laboratory (LLNL), Livermore, CA (2013).}. This permits the compounds to maintain high densities while controlling their stability and sensitivity. Due to the nature of energetic phenomena, varying pressure (and thus density) is a valuable tool to explore the properties of these materials. We will present data on LLM-172 compressed in diamond anvil cells to 50 GPa and characterized by Raman spectroscopy and synchrotron powder x-ray diffraction. These techniques allow for the exploration of the evolution of the structure and bonding with pressure. In particular, we will examine the changes as the sample approaches the detonation pressure (near 34 GPa)\footnote[2]{J. J. Sabatini and K. D. Oyler, \emph{Crystals} \textbf{6}, 5 (2016)}. [Preview Abstract] |
Monday, March 13, 2017 4:30PM - 4:42PM |
C2.00009: Sound velocity of liquid Fe–S alloy in diamond-anvil cell via inelastic X-ray scattering measurements Saori Kawaguchi, Yoichi Nakajima, Kei Hirose, Tetsuya Komabayashi, Haruka Tateno, Shigehiko Tateno, Yasuhiro Kuwayama, Guillaume Morard, Hiroshi Uchiyama, Satoshi Tsutsui, Alfred Baron We have developed a new method and investigated sound velocity of liquid Fe-Ni-S alloys at high pressure up to 52 GPa in both externally-resistance-heated and laser-heated diamond-anvil cells using high-resolution inelastic X-ray scattering measurements (IXS) at SPring-8 with energy resolution of 2.8 meV at 17.79 keV. The X-ray beam was focused to 17 $\mu$$m^{2}$ area by a KB focusing mirror optics. At each $P$-$T$ condition, IXS spectra were collected at different momentum transfers ($Q$) using an array of twelve independent analyzers. The $Q$ range was 3.2 - 6.6 nm$^{-1}$ with resolution of 0.4 nm$^{-1}$ full width. Each spectrum was obtained in an energy range of -30 to 40 meV. Melting of the sample was determined by angle-dispersive X-ray diffraction spectra obtained before IXS measurements. We determined the elastic parameters of liquid Fe$_{47}$Ni$_{28}$S$_{25}$ to be $K_{SO}$ = 95.3 (27) GPa and $K_{SO}$’ = 3.98 (13), where $K_{SO}$ and $K_{SO}$’ are the adiabatic bulk modulus and its pressure derivative at zero pressure, when fixing the density at 5.58 g/cm$^{3}$ for 1 bar and 2000 K. Both sound velocity and density observed for the Earth's outer core can be explained by adding 5.8-7.0 wt. percent sulfur in the liquid iron. [Preview Abstract] |
Monday, March 13, 2017 4:42PM - 4:54PM |
C2.00010: Abstract Withdrawn
|
Monday, March 13, 2017 4:54PM - 5:06PM |
C2.00011: Effect of pressure on Zircon's (ZrSiO$_4$) Raman active modes: a first-principles study Natalya Sheremetyeva, Daniele Cherniak, Bruce Watson, Vincent Meunier Zircon is a mineral commonly found in the Earth crust. Its remarkable properties have given rise to considerable attention. This includes possible inclusion of radioactive elements in natural samples, which allows for geochronological investigations. Subsequently, Zircon was proposed as possible host material for radioactive waste management. Internal radiation damage in zircon leads to the destruction of its crystal structure (an effect known as metamictization) which is subject to ongoing research. Recently, the effect of pressure and temperature on synthetic zircon has been analyzed experimentally using Raman spectroscopy (Schmidt et al., Am. Min. 98, 643 (2013)) which led to the calibration of zircon as a pressure sensor in diamond-anvil cell experiments. While there have been a number of theoretical studies, the effect of pressure on the Raman active modes of zircon has not been investigated theoretically. Here we present a first-principles pressure calibration of the Raman active modes in Zircon employing density-functional theory (DFT). We find excellent quantitative agreement of the slopes $\partial\omega/\partial P$ with the experimental ones and are able to rationalize the $\omega$ vs. $P$ behavior based on the details of the vibrational modes. [Preview Abstract] |
Monday, March 13, 2017 5:06PM - 5:18PM |
C2.00012: Particle evolution of Composition B-3 studied by time-resolved small angle x-ray scattering R Huber, D Podlesak, D Dattelbaum, M Firestone, R Gustavsen, B Jensen, B Ringstrand, E Watkins, M Bagge-Hansen, R Hodgin, L Lauderbach, T Willey, T van Buuren, T Graber, P Rigg, N Sinclair, S Seifert Accessing various pressures and temperatures of the carbon phase diagram through high explosive (HE) detonations, as a means of synthesis, provides an exciting opportunity to study new carbon allotropes. Carbon allotropes in HE detonations are thought to form through collision of free carbon within the detonation cloud; however direct confirmation of real-time product formation is limited due to experimental restraints. Time-resolved small angle x-ray scattering (TRSAXS) of in-line detonations provides information about particle formation behind the detonation front on the 100's of nanoseconds timescale. The only set-up of its kind in the United States is at Argonne National Laboratory at the Advanced Photon Source in the Dynamic Compression Sector (DCS). Through empirical and analytical analysis of the TRSAXS data, parameters such as particle size and morphology can be deduced with respect to time. In the case of Composition B-3 (40{\%} TNT/60{\%} RDX) particle formation morphs from spherical core-shell structure to an elongated structure at long times (\textasciitilde 2 us) under vacuum. To complete the timeline of carbon formation, the post detonation soot is also analyzed to confirm this elongated structure as the majority carbon product. LA-UR-16-28691 [Preview Abstract] |
Monday, March 13, 2017 5:18PM - 5:30PM |
C2.00013: Kinetics of carbon clustering in detonation of high explosives: Does theory match experiment? Kirill Velizhanin, Joshua Coe Chemical reactions in detonation of carbon-rich high explosives yield solid carbon as a major constituent of the products. Efforts to theoretically describe the kinetics of carbon clustering go back to the seminal paper by Shaw and Johnson, where it was modeled as a diffusion-limited irreversible coagulation of smaller clusters into larger ones. However, first direct experimental observations of the kinetics of clustering yielded cluster growth one to two orders of magnitude slower than theoretical predictions. Multiple efforts were undertaken to test and revise the basic assumptions of the model in order to achieve better agreement with experiment. In this talk I will discuss our very recent direct experimental observations of carbon cluster growth in detonation of high explosives, based on time-resolved small-angle X-ray scattering (TR-SAXS). I will focus on comparison of these results to simulations using the modified Shaw-Johnson model and demonstrate that these new results are in much better agreement with the model than before. The implications of this much better agreement on our present understanding of in-detonation carbon clustering processes and possible ways to increase the agreement between theory and experiment even further will be discussed. [Preview Abstract] |
Follow Us |
Engage
Become an APS Member |
My APS
Renew Membership |
Information for |
About APSThe American Physical Society (APS) is a non-profit membership organization working to advance the knowledge of physics. |
© 2024 American Physical Society
| All rights reserved | Terms of Use
| Contact Us
Headquarters
1 Physics Ellipse, College Park, MD 20740-3844
(301) 209-3200
Editorial Office
100 Motor Pkwy, Suite 110, Hauppauge, NY 11788
(631) 591-4000
Office of Public Affairs
529 14th St NW, Suite 1050, Washington, D.C. 20045-2001
(202) 662-8700