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Bai Z, Beck NB, Scheibe B, Sperling JM, Weiland A, Ruf M, Brannon JP, Rotermund BM, Gomez Martinez D, Albrecht-Schönzart TE. Investigation of Pressure Effects in the Bimetallic Transplutonium Tetrazolate Complexes [(An(pmtz) 2(H 2O) 3) 2(μ-pmtz)] 2(pmtz) 2· nH 2O (An 3+ = Cm 3+, Bk 3+, and Cf 3+). J Am Chem Soc 2024; 146:7822-7830. [PMID: 38456811 DOI: 10.1021/jacs.4c00803] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/09/2024]
Abstract
Understanding the effects of pressure on actinide compounds is an integral part of safe nuclear waste storage in deep geologic repositories and provides a means of systematically altering the structure and properties. However, detailing how the effects of pressure evolve across the actinide series in the later elements is not typically undertaken because of the challenges of conducting research on these unstable isotopes. Here, a family of bimetallic actinide complexes, [(An(pmtz)2(H2O)3)2(μ-pmtz)]2(pmtz)2·nH2O (An3+ = Cm3+, Bk3+, and Cf3+, pmtz- = 5-(pyrimidyl)tetrazolate; Cm1, Bk1, and Cf1), are reported and represent the first structurally characterized bimetallic berkelium and californium compounds. The pressure response as determined from UV-vis-NIR transitions varies for Cm1, Bk1, and Cf1. The 5f → 5f transitions in Cm1 are notably more sensitive to pressure compared to those in Bk1 and Cf1 and show substantial bathochromic shifting of several 5f → 5f transitions. In the case of Bk1, an ingrowth of a metal-to-ligand charge-transfer transition occurs at elevated pressures because of the accessible Bk3+/Bk4+ couple. For Cf1, no substantial transition shifting or emergence of MLCT transitions is observed at elevated pressures because of the prohibitive energetics of the Cf3+/Cf4+ couple and reduced sensitivity of the 5f → 5f transitions to the local coordination environment because of the more contracted 5f shell versus Cm3+ and Bk3+.
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Affiliation(s)
- Zhuanling Bai
- Department of Chemistry and Nuclear Science & Engineering Center, Colorado School of Mines, Golden, Colorado 80401, United States
| | - Nicholas B Beck
- Department of Chemistry and Nuclear Science & Engineering Center, Colorado School of Mines, Golden, Colorado 80401, United States
| | - Benjamin Scheibe
- Department of Chemistry and Nuclear Science & Engineering Center, Colorado School of Mines, Golden, Colorado 80401, United States
| | - Joseph M Sperling
- Department of Chemistry and Nuclear Science & Engineering Center, Colorado School of Mines, Golden, Colorado 80401, United States
| | - Ashley Weiland
- Bruker AXS, 5465 E Cheryl Pkwy, Fitchburg, Madison, Wisconsin 53711, United States
| | - Michael Ruf
- Bruker AXS, 5465 E Cheryl Pkwy, Fitchburg, Madison, Wisconsin 53711, United States
| | - Jacob P Brannon
- Department of Chemistry and Nuclear Science & Engineering Center, Colorado School of Mines, Golden, Colorado 80401, United States
| | - Brian M Rotermund
- Department of Chemistry and Nuclear Science & Engineering Center, Colorado School of Mines, Golden, Colorado 80401, United States
| | - Daniela Gomez Martinez
- Department of Chemistry and Nuclear Science & Engineering Center, Colorado School of Mines, Golden, Colorado 80401, United States
| | - Thomas E Albrecht-Schönzart
- Department of Chemistry and Nuclear Science & Engineering Center, Colorado School of Mines, Golden, Colorado 80401, United States
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2
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Murphy GL, Kegler P, Alekseev EV. Advances and perspectives of actinide chemistry from ex situ high pressure and high temperature chemical studies. Dalton Trans 2022; 51:7401-7415. [PMID: 35475437 DOI: 10.1039/d2dt00697a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
High pressure high temperature (HP/HT) studies of actinide compounds allow the chemistry and bonding of among the most exotic elements in the periodic table to be examined under the conditions often only found in the severest environments of nature. Peering into this realm of physical extremity, chemists have extracted detailed knowledge of the fundamental chemistry of actinide elements and how they contribute to bonding, structure formation and intricate properties in compounds under such conditions. The last decade has resulted in some of the most significant contributions to actinide chemical science and this holds true for ex situ chemical studies of actinides resulting from HP/HT conditions of over 1 GPa and elevated temperature. Often conducted in tandem with ab initio calculations, HP/HT studies of actinides have further helped guide and develop theoretical modelling approaches and uncovered associated difficulties. Accordingly, this perspective article is devoted to reviewing the latest advancements made in actinide HP/HT ex situ chemical studies over the last decade, the state-of-the-art, challenges and discussing potential future directions of the science. The discussion is given with emphasis on thorium and uranium compounds due to the prevalence of their investigation but also highlights some of the latest advancements in high pressure chemical studies of transuranium compounds. The perspective also describes technical aspects involved in HP/HT investigation of actinide compounds.
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Affiliation(s)
- Gabriel L Murphy
- Institute of Energy and Climate Research, Forschungszentrum Jülich GmbH, 52428 Jülich, Germany.
| | - Philip Kegler
- Institute of Energy and Climate Research, Forschungszentrum Jülich GmbH, 52428 Jülich, Germany.
| | - Evgeny V Alekseev
- Institute of Energy and Climate Research, Forschungszentrum Jülich GmbH, 52428 Jülich, Germany.
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3
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McMahon MI. Probing extreme states of matter using ultra-intense x-ray radiation. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2021; 34:043001. [PMID: 33725673 DOI: 10.1088/1361-648x/abef26] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/29/2020] [Accepted: 03/16/2021] [Indexed: 06/12/2023]
Abstract
Extreme states of matter, that is, matter at extremes of density (pressure) and temperature, can be created in the laboratory either statically or dynamically. In the former, the pressure-temperature state can be maintained for relatively long periods of time, but the sample volume is necessarily extremely small. When the extreme states are generated dynamically, the sample volumes can be larger, but the pressure-temperature conditions are maintained for only short periods of time (ps toμs). In either case, structural information can be obtained from the extreme states by the use of x-ray scattering techniques, but the x-ray beam must be extremely intense in order to obtain sufficient signal from the extremely-small or short-lived sample. In this article I describe the use of x-ray diffraction at synchrotrons and XFELs to investigate how crystal structures evolve as a function of density and temperature. After a brief historical introduction, I describe the developments made at the Synchrotron Radiation Source in the 1990s which enabled the almost routine determination of crystal structure at high pressures, while also revealing that the structural behaviour of materials was much more complex than previously believed. I will then describe how these techniques are used at the current generation of synchrotron and XFEL sources, and then discuss how they might develop further in the future at the next generation of x-ray lightsources.
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Affiliation(s)
- M I McMahon
- SUPA, School of Physics and Astronomy, and Centre for Science at Extreme Conditions, The University of Edinburgh, Peter Guthrie Tait Road, Edinburgh, EH9 3FD, United Kingdom
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Caciuffo R, Lander GH. X-ray synchrotron radiation studies of actinide materials. JOURNAL OF SYNCHROTRON RADIATION 2021; 28:1692-1708. [PMID: 34738923 PMCID: PMC8570219 DOI: 10.1107/s1600577521009413] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 07/01/2021] [Accepted: 09/09/2021] [Indexed: 06/13/2023]
Abstract
By reviewing a selection of X-ray diffraction (XRD), resonant X-ray scattering (RXS), X-ray magnetic circular dichroism (XMCD), resonant and non-resonant inelastic scattering (RIXS, NIXS), and dispersive inelastic scattering (IXS) experiments, the potential of synchrotron radiation techniques in studying lattice and electronic structure, hybridization effects, multipolar order and lattice dynamics in actinide materials is demonstrated.
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Affiliation(s)
- Roberto Caciuffo
- European Commission, Joint Research Centre, Postfach 2340, D-76125 Karlsruhe, Germany
| | - Gerard H. Lander
- European Commission, Joint Research Centre, Postfach 2340, D-76125 Karlsruhe, Germany
- Interface Analysis Centre, School of Physics, University of Bristol, Tyndall Avenue, Bristol BS8 1TL, United Kingdom
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Zhou ZZ, Fan DD, Liu HJ, Liu J. High figure-of-merit in the heavy-fermion UN 2 system for radioisotope thermoelectric applications. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2021; 33:015601. [PMID: 33052894 DOI: 10.1088/1361-648x/abb0a6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
The design of uranium-based thermoelectric (TE) materials presents a novel and intriguing strategy for directly converting nuclear heat into electrical power. Using high-level first-principles approach combined with accurate solution of Boltzmann transport equation, we demonstrate that a giant n-type power factor of 13.8 mW m-1 K-2 and a peak ZT value of 2.2 can be realized in the heavy-fermion UN2 compound at 700 K. Such promising TE performance arises from the large degeneracy (N v = 14) of heavy conduction band coupled with weak electron-phonon interactions, which is in principle governed by the strong Coulomb correlation among the partially filled U-5f electrons in the face-centered cubic structure. Collectively, our theoretical work suggests that the energetic UN2 could serve as both excellent heat source and efficient power convertor, which also uncovers an underexplored area for TE research.
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Affiliation(s)
- Z Z Zhou
- Key Laboratory of Artificial Micro- and Nano-Structures of Ministry of Education and School of Physics and Technology, Wuhan University, Wuhan 430072, People's Republic of China
| | - D D Fan
- Key Laboratory of Artificial Micro- and Nano-Structures of Ministry of Education and School of Physics and Technology, Wuhan University, Wuhan 430072, People's Republic of China
| | - H J Liu
- Key Laboratory of Artificial Micro- and Nano-Structures of Ministry of Education and School of Physics and Technology, Wuhan University, Wuhan 430072, People's Republic of China
| | - J Liu
- Institute of Materials, China Academy of Engineering Physics, Mianyang 621907, People's Republic of China
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Dala NJ, Zhong-Wen W, Xiao-Bin D, Lu-You X, Chen-Zhong D. The effect of 5 f states on the nd → 5 f transition energies and spectra of americium ions. IOP SCINOTES 2020. [DOI: 10.1088/2633-1357/abbd2b] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
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Compression of curium pyrrolidine-dithiocarbamate enhances covalency. Nature 2020; 583:396-399. [DOI: 10.1038/s41586-020-2479-2] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2019] [Accepted: 04/21/2020] [Indexed: 12/22/2022]
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8
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Yang JW, An L. Structure, elastic characteristic, ideal strengths, and phonon stability of binary uranium intermetallic UGe 3 of AuCu 3-type. Phys Chem Chem Phys 2020; 22:1381-1391. [PMID: 31858101 DOI: 10.1039/c9cp04971a] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Crystallographic characterization, energy band structure, densities of states and charge density, elastic properties, ideal tensile and shear strengths, lattice dynamics and thermophysical characteristics of UGe3 of AuCu3-type have been studied by employing the first principles method based on Density Functional Theory (DFT). The optimized lattice parameters, such as lattice constant a, equilibrium cell volume V0, U-Ge distance and U-U distance of UGe3, are in favorable agreement with the available experimental results. Three single-crystalline elastic constants of C11, C12, and C44 have been obtained using the "energy-strain" technique by increasingly varying small strains. The polycrystalline elastic moduli including volume modulus B, Young's modulus E, and shear modulus G, Poisson's ratio v, brittle/ductile nature, Debye temperature θD, and the integration of elastic wave velocities over different crystallographic directions have also been successfully calculated. The anisotropy of the three-directional bulk modulus and Young's modulus is systematically explored and analyzed. The calculations indicate that UGe3 of AuCu3-type should be stabilized mechanically, and the system possesses insignificant elastic anisotropy. In particular, the vibrational spectrum, phonon densities of states and the infrared-active and inactive vibration modes at the center of the Brillouin zone are determined using Density Functional Perturbation Theory (DFPT) and group theory for the first time. This study reveals that UGe3 of AuCu3-type is also stable dynamically. Finally, within the calculated phonon densities of states and the quasi-harmonic Debye model, the constant volume heat capacity Cv and the vibration entropy S in the temperature range of 0-1000 K are predicted and analyzed comprehensively. The present investigations are expected to provide some valuable references for further exploring the properties of uranium compounds.
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Affiliation(s)
- Jin-Wen Yang
- Department of Physics, Taiyuan Normal University, Jinzhong 030619, China.
| | - Li An
- Department of Physics, Taiyuan Normal University, Jinzhong 030619, China.
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Jian T, Dau PD, Shuh DK, Vasiliu M, Dixon DA, Peterson KA, Gibson JK. Activation of Water by Pentavalent Actinide Dioxide Cations: Characteristic Curium Revealed by a Reactivity Turn after Americium. Inorg Chem 2019; 58:14005-14014. [DOI: 10.1021/acs.inorgchem.9b01997] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Tian Jian
- Chemical Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, United States
| | - Phuong Diem Dau
- Chemical Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, United States
| | - David K. Shuh
- Chemical Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, United States
| | - Monica Vasiliu
- Department of Chemistry and Biochemistry, University of Alabama, Tuscaloosa, Alabama 35401, United States
| | - David A. Dixon
- Department of Chemistry and Biochemistry, University of Alabama, Tuscaloosa, Alabama 35401, United States
| | - Kirk A. Peterson
- Department of Chemistry, Washington State University, Pullman, Washington 99164, United States
| | - John K. Gibson
- Chemical Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, United States
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Amadon B, Dorado B. A unified and efficient theory for the structural properties of actinides and phases of plutonium. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2018; 30:405603. [PMID: 30136656 DOI: 10.1088/1361-648x/aadc7a] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
We show that a calculation using density functional theory (DFT) in the generalized gradient approximation (GGA) supplemented by an explicit Coulomb interaction term between correlated electrons (GGA+U), can accurately describe structural properties of (1) the room temperature phases of U, Np, Pu, Am and Cm, and (2) the α, β, γ, δ and ϵ phases of plutonium, as does the combination of GGA with dynamical mean field theory (DMFT). It thus changes the view on the role of electronic interaction in these systems and opens the way to fast calculations of structural properties in actinides metallic system. We use ab initio values of effective Coulomb interactions and underline that Hund's exchange and spin-orbit coupling are of utmost importance in these calculations. Secondly, we show that phonons properties in δ plutonium are impacted by strong interactions. The GGA+DMFT results exhibits a lattice instability for the transverse (1 1 1) phonon mode. Moreover the amplitude of this lattice instability is consistent with the experimental temperature of stability of this phase. Our calculation thus shows that when the δ phase is thermodynamically unstable (at 0 K), it is also dynamically unstable.
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11
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Rittman DR, Turner KM, Park S, Fuentes AF, Park C, Ewing RC, Mao WL. Strain engineered pyrochlore at high pressure. Sci Rep 2017; 7:2236. [PMID: 28533513 PMCID: PMC5440404 DOI: 10.1038/s41598-017-02637-9] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2016] [Accepted: 04/13/2017] [Indexed: 11/30/2022] Open
Abstract
Strain engineering is a promising method for next-generation materials processing techniques. Here, we use mechanical milling and annealing followed by compression in diamond anvil cell to tailor the intrinsic and extrinsic strain in pyrochlore, Dy2Ti2O7 and Dy2Zr2O7. Raman spectroscopy, X-ray pair distribution function analysis, and X-ray diffraction were used to characterize atomic order over short-, medium-, and long-range spatial scales, respectively, under ambient conditions. Raman spectroscopy and X-ray diffraction were further employed to interrogate the material in situ at high pressure. High-pressure behavior is found to depend on the species and concentration of defects in the sample at ambient conditions. Overall, we show that defects can be engineered to lower the phase transformation onset pressure by ~50% in the ordered pyrochlore Dy2Ti2O7, and lower the phase transformation completion pressure by ~20% in the disordered pyrochlore Dy2Zr2O7. These improvements are achieved without significantly sacrificing mechanical integrity, as characterized by bulk modulus.
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Affiliation(s)
- Dylan R Rittman
- Department of Geological Sciences, Stanford University, Stanford, California, 94305, USA.
| | - Katlyn M Turner
- Department of Geological Sciences, Stanford University, Stanford, California, 94305, USA
| | - Sulgiye Park
- Department of Geological Sciences, Stanford University, Stanford, California, 94305, USA
| | - Antonio F Fuentes
- Cinvestav Unidad Saltillo, Apartado Postal 663, 25000, Saltillo, Coahuila, Mexico
| | - Changyong Park
- High Pressure Collaborative Access Team, Geophysical Laboratory, Carnegie Institution of Washington, Argonne, IL, 60439, USA
| | - Rodney C Ewing
- Department of Geological Sciences, Stanford University, Stanford, California, 94305, USA
| | - Wendy L Mao
- Department of Geological Sciences, Stanford University, Stanford, California, 94305, USA.,Stanford Institute for Materials and Energy Sciences, SLAC National Accelerator Laboratory, Menlo Park, California, 94025, USA
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12
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Serezhkin VN, Savchenkov AV, Serezhkina LB. Crystal-chemical features of baric polymorphism of actinides. RADIOCHEMISTRY 2017. [DOI: 10.1134/s1066362217010027] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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13
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Serezhkin VN, Savchenkov AV, Pushkin DV, Serezhkina LB. Crystal-chemical features of thermal polymorphism of actinides. RADIOCHEMISTRY 2016. [DOI: 10.1134/s1066362216060011] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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14
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Cary SK, Silver MA, Liu G, Wang JC, Bogart JA, Stritzinger JT, Arico AA, Hanson K, Schelter EJ, Albrecht-Schmitt TE. Spontaneous Partitioning of Californium from Curium: Curious Cases from the Crystallization of Curium Coordination Complexes. Inorg Chem 2015; 54:11399-404. [DOI: 10.1021/acs.inorgchem.5b02052] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Samantha K. Cary
- Department of Chemistry and Biochemistry, Florida State University, Tallahassee, Florida 32306, United States
| | - Mark A. Silver
- Department of Chemistry and Biochemistry, Florida State University, Tallahassee, Florida 32306, United States
| | - Guokui Liu
- Chemical
Sciences and Engineering Division, Argonne National Laboratory, Argonne, Illinois 60439, United States
| | - Jamie C. Wang
- Department of Chemistry and Biochemistry, Florida State University, Tallahassee, Florida 32306, United States
| | - Justin A. Bogart
- P. Roy and Diana T. Vagelos Laboratories,
Department of Chemistry, University of Pennsylvania, 231 South 34th Street, Philadelphia, Pennsylvania 19104, United States
| | - Jared T. Stritzinger
- Department of Chemistry and Biochemistry, Florida State University, Tallahassee, Florida 32306, United States
| | - Alexandra A. Arico
- Department of Chemistry and Biochemistry, Florida State University, Tallahassee, Florida 32306, United States
| | - Kenneth Hanson
- Department of Chemistry and Biochemistry, Florida State University, Tallahassee, Florida 32306, United States
| | - Eric J. Schelter
- P. Roy and Diana T. Vagelos Laboratories,
Department of Chemistry, University of Pennsylvania, 231 South 34th Street, Philadelphia, Pennsylvania 19104, United States
| | - Thomas E. Albrecht-Schmitt
- Department of Chemistry and Biochemistry, Florida State University, Tallahassee, Florida 32306, United States
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Phase Transitions and Structural Stability of Binary Uranium Intermetallics Under High Pressure: A Review. PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES INDIA SECTION A-PHYSICAL SCIENCES 2012. [DOI: 10.1007/s40010-012-0034-8] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
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16
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Polinski MJ, Wang S, Alekseev EV, Depmeier W, Liu G, Haire RG, Albrecht-Schmitt TE. Curium(III) Borate Shows Coordination Environments of Both Plutonium(III) and Americium(III) Borates. Angew Chem Int Ed Engl 2012; 51:1869-72. [DOI: 10.1002/anie.201107956] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2011] [Indexed: 11/08/2022]
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17
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Polinski MJ, Wang S, Alekseev EV, Depmeier W, Liu G, Haire RG, Albrecht-Schmitt TE. Curium(III) Borate Shows Coordination Environments of Both Plutonium(III) and Americium(III) Borates. Angew Chem Int Ed Engl 2012. [DOI: 10.1002/ange.201107956] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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18
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Raymond S, Bouchet J, Lander GH, Le Tacon M, Garbarino G, Hoesch M, Rueff JP, Krisch M, Lashley JC, Schulze RK, Albers RC. Understanding the complex phase diagram of uranium: the role of electron-phonon coupling. PHYSICAL REVIEW LETTERS 2011; 107:136401. [PMID: 22026877 DOI: 10.1103/physrevlett.107.136401] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/04/2011] [Indexed: 05/31/2023]
Abstract
We report an experimental determination of the dispersion of the soft phonon mode along [100] in uranium as a function of pressure. The energies of these phonons increase rapidly, with conventional behavior found by 20 GPa, as predicted by recent theory. New calculations demonstrate the strong pressure (and momentum) dependence of the electron-phonon coupling, whereas the Fermi-surface nesting is surprisingly independent of pressure. This allows a full understanding of the complex phase diagram of uranium and the interplay between the charge-density wave and superconductivity.
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Affiliation(s)
- S Raymond
- SPSMS, UMR-E, CEA-INAC/UJF-Grenoble, France
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Samudrala GK, Thomas SA, Montgomery JM, Vohra YK. High pressure phase transitions in the rare earth metal erbium to 151 GPa. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2011; 23:315701. [PMID: 21753243 DOI: 10.1088/0953-8984/23/31/315701] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
High pressure x-ray diffraction studies have been performed on the heavy rare earth metal erbium (Er) in a diamond anvil cell at room temperature to a pressure of 151 GPa and Er has been compressed to 40% of its initial volume. The rare earth crystal structure sequence hcp → Sm type → dhcp → distorted fcc (hcp: hexagonal close packed; fcc: face centered cubic; dhcp: double hcp) is observed in Er below 58 GPa. We have carried out Rietveld refinement of crystal structures in the pressure range between 58 GPa and 151 GPa. We have examined various crystal structures that have been proposed for the distorted fcc (dfcc) phase and the post-dfcc phase in rare earth metals. We find that the hexagonal hR 24 structure is the best fit between 58 and 118 GPa. Above 118 GPa, a structural transformation from hR 24 phase to a monoclinic C 2/m phase is observed with a volume change of - 1.9%. We have also established a clear trend for the pressure at which a post-dfcc phase is formed in rare earth metals and show that there is a monotonic increase in this pressure with the filling of 4f shell.
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Affiliation(s)
- Gopi K Samudrala
- Department of Physics, University of Alabama at Birmingham, Birmingham, AL 35294, USA
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Montgomery JM, Samudrala GK, Tsoi GM, Vohra YK. High-pressure phase transitions in rare earth metal thulium to 195 GPa. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2011; 23:155701. [PMID: 21460429 DOI: 10.1088/0953-8984/23/15/155701] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
We have performed image plate x-ray diffraction studies on a heavy rare earth metal, thulium (Tm), in a diamond anvil cell to a pressure of 195 GPa and volume compression V/V₀ = 0.38 at room temperature. The rare earth crystal structure sequence, hcp →Sm-type→ dhcp →fcc → distorted fcc, is observed in Tm below 70 GPa with the exception of a pure fcc phase. The focus of our study is on the ultrahigh-pressure phase transition and Rietveld refinement of crystal structures in the pressure range between 70 and 195 GPa. The hexagonal hR-24 phase is seen to describe the distorted fcc phase between 70 and 124 GPa. Above 124 ± 4 GPa, a structural transformation from hR 24 phase to a monoclinic C 2/m phase is observed with a volume change of -1.5%. The equation of state data shows rapid stiffening above the phase transition at 124 GPa and is indicative of participation of f-electrons in bonding. We compare the behavior of Tm to other heavy rare-earths and heavy actinide metals under extreme conditions of pressure.
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Affiliation(s)
- Jeffrey M Montgomery
- Department of Physics, University of Alabama at Birmingham (UAB), Birmingham, AL 35294, USA
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Vohra YK, Sangala BR, Stemshorn AK, Hope KM. High Pressure Phase Transformations in Heavy Rare Earth Metals and Connections to Actinide Crystal Structures. ACTA ACUST UNITED AC 2011. [DOI: 10.1557/proc-1104-nn01-04] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
AbstractHigh-pressure studies have been performed on heavy rare earth metals Terbium (Tb) to 155 GPa and Holmium (Ho) to 134 GPa in a diamond anvil cell at room temperature. The following crystal structure sequence was observed in both metals hcp ⟶ Sm-type ⟶ dhcp ⟶ distorted fcc (hR-24) ⟶ monoclinic (C2/m) with increasing pressure. The last transformation to a low symmetry monoclinic phase is accompanied by a volume collapse of 5 % for Tb at 51 GPa and a volume collapse of 3 % for Ho at 103 GPa. This volume collapse under high pressure is reminiscent of f-shell delocalization in light rare earth metal Cerium (Ce), Praseodymium (Pr), and heavy actinide metals Americium (Am) and Curium (Cm). The orthorhombic Pnma phase that has been reported in Am and Cm after f-shell delocalization is not observed in heavy rare earth metals under high pressures.
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Lukoyanov AV, Shorikov AO, Bystrushkin VB, Dyachenko AA, Kabirova LR, Tsiovkin YY, Povzner AA, Dremov VV, Korotin MA, Anisimov VI. Electronic structure and magnetic state of transuranium metals under pressure. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2010; 22:495501. [PMID: 21406785 DOI: 10.1088/0953-8984/22/49/495501] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
The electronic structures of bcc Np, fcc Pu, Am, and Cm pure metals under pressure have been investigated employing the LDA + U method with spin-orbit coupling (LDA + U + SO). The magnetic state of the actinide ions was analyzed in both LS and jj coupling schemes to reveal the applicability of corresponding coupling bases. It was demonstrated that whereas Pu and Am are well described within the jj coupling scheme, Np and Cm can be described appropriately neither in a {mσ}, nor in a {jmj} basis, due to intermediate coupling scheme realization in these metals that requires some finer treatment. The LDA + U + SO results for the considered transuranium metals reveal band broadening and gradual 5f electron delocalization under pressure.
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Affiliation(s)
- A V Lukoyanov
- Institute of Metal Physics, Russian Academy of Sciences-Ural Division, 620990 Yekaterinburg, Russia. Ural Federal University, 620002 Yekaterinburg, Russia
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Moore KT. X-ray and electron microscopy of actinide materials. Micron 2010; 41:336-58. [DOI: 10.1016/j.micron.2009.12.006] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2009] [Revised: 12/15/2009] [Accepted: 12/15/2009] [Indexed: 11/30/2022]
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Moore KT, van der Laan G, Haire RG, Wall MA, Schwartz AJ, Söderlind P. Emergence of strong exchange interaction in the actinide series: the driving force for magnetic stabilization of curium. PHYSICAL REVIEW LETTERS 2007; 98:236402. [PMID: 17677923 DOI: 10.1103/physrevlett.98.236402] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/09/2007] [Indexed: 05/16/2023]
Abstract
Using electron energy-loss spectroscopy, many-electron atomic spectral calculations, and density functional theory, we show that angular-momentum coupling in the 5f states plays a decisive role in the formation of the magnetic moment in Cm metal. The 5f states of Cm in intermediate coupling are strongly shifted towards the LS coupling limit due to exchange interaction, unlike most actinide elements where the effective spin-orbit interaction prevails. Hund's rule coupling is the key to producing the large spin polarization that dictates the newly found crystal structure of Cm under pressure.
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Affiliation(s)
- K T Moore
- Lawrence Livermore National Laboratory, Livermore, California 94550, USA.
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Perez-Mato JM, Elcoro L, Aroyo MI, Katzke H, Tolédano P, Izaola Z. Apparently complex high-pressure phase of gallium as a simple modulated structure. PHYSICAL REVIEW LETTERS 2006; 97:115501. [PMID: 17025897 DOI: 10.1103/physrevlett.97.115501] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/04/2006] [Indexed: 05/12/2023]
Abstract
The phase of gallium GaII, with symmetry C222(1) and 104 atoms per unit cell, has been recently reported as an example of structural complexity under high pressure. It is shown here that this phase is a simple modulated distortion of an average structure of Fddd symmetry with all atoms structurally equivalent. The modulation can be described with only 4 parameters and satisfies symmetry properties described by a centrosymmetric superspace group. The structural distortion is dominated by a frozen transversal mode associated with a single irreducible representation of Fddd, with a wave vector on the line Q, at an edge of the Brillouin zone. The average structure can be related with an hcp configuration through simple sliding of hcp layers, reminiscent of the hcp-bcc Bürgers mechanism.
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Affiliation(s)
- J M Perez-Mato
- Departamento de Física de la Materia Condensada, Facultad de Ciencia y Tecnología, Universidad del País Vasco, Apdo 644, 48080 Bilbao, Spain
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