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Düllmann CE, Block M, Heßberger FP, Khuyagbaatar J, Kindler B, Kratz JV, Lommel B, Münzenberg G, Pershina V, Renisch D, Schädel M, Yakushev A. Five decades of GSI superheavy element discoveries and chemical investigation. RADIOCHIM ACTA 2022. [DOI: 10.1515/ract-2022-0015] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
Abstract
Superheavy element research has been a strong pillar of the research program at GSI Darmstadt since its foundation. Six new elements were discovered along with many new isotopes. Initial results on chemical properties of the heaviest elements were obtained that allowed for comparing their behavior with that of their lighter homologs and with theoretical predictions. Main achievements of the past five decades of superheavy element research at GSI are described along with an outlook into the future of superheavy element research in Darmstadt.
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Affiliation(s)
- Christoph E. Düllmann
- GSI Helmholtzzentrum für Schwerionenforschung GmbH , Planckstr. 1, 64291 Darmstadt , Germany
- Department Chemie – Standort TRIGA , Johannes Gutenberg-Universität Mainz , Fritz-Strassmann-Weg 2, 55128 Mainz , Germany
- Helmholtz-Institut Mainz , Staudingerweg 18, 55128 Mainz , Germany
| | - Michael Block
- GSI Helmholtzzentrum für Schwerionenforschung GmbH , Planckstr. 1, 64291 Darmstadt , Germany
- Department Chemie – Standort TRIGA , Johannes Gutenberg-Universität Mainz , Fritz-Strassmann-Weg 2, 55128 Mainz , Germany
- Helmholtz-Institut Mainz , Staudingerweg 18, 55128 Mainz , Germany
| | - Fritz P. Heßberger
- GSI Helmholtzzentrum für Schwerionenforschung GmbH , Planckstr. 1, 64291 Darmstadt , Germany
| | - Jadambaa Khuyagbaatar
- GSI Helmholtzzentrum für Schwerionenforschung GmbH , Planckstr. 1, 64291 Darmstadt , Germany
| | - Birgit Kindler
- GSI Helmholtzzentrum für Schwerionenforschung GmbH , Planckstr. 1, 64291 Darmstadt , Germany
| | - Jens V. Kratz
- Department Chemie – Standort TRIGA , Johannes Gutenberg-Universität Mainz , Fritz-Strassmann-Weg 2, 55128 Mainz , Germany
| | - Bettina Lommel
- GSI Helmholtzzentrum für Schwerionenforschung GmbH , Planckstr. 1, 64291 Darmstadt , Germany
| | - Gottfried Münzenberg
- GSI Helmholtzzentrum für Schwerionenforschung GmbH , Planckstr. 1, 64291 Darmstadt , Germany
- Institut für Physik, Johannes Gutenberg-Universität Mainz , Staudingerweg 7, 55128 Mainz , Germany
| | - Valeria Pershina
- GSI Helmholtzzentrum für Schwerionenforschung GmbH , Planckstr. 1, 64291 Darmstadt , Germany
| | - Dennis Renisch
- Department Chemie – Standort TRIGA , Johannes Gutenberg-Universität Mainz , Fritz-Strassmann-Weg 2, 55128 Mainz , Germany
- Helmholtz-Institut Mainz , Staudingerweg 18, 55128 Mainz , Germany
| | - Matthias Schädel
- GSI Helmholtzzentrum für Schwerionenforschung GmbH , Planckstr. 1, 64291 Darmstadt , Germany
| | - Alexander Yakushev
- GSI Helmholtzzentrum für Schwerionenforschung GmbH , Planckstr. 1, 64291 Darmstadt , Germany
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Tarselli MA. Hidden hassium. Nat Chem 2018; 10:482. [PMID: 29568053 DOI: 10.1038/s41557-018-0037-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Affiliation(s)
- Michael A Tarselli
- NIBR Informatics (NX), Novartis Institutes for BioMedical Research, Cambridge, MA, USA.
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Abstract
In nuclear physics, superheavy and hypernuclei are two of the most important fields of research. The prediction of islands of superheavy elements (Z = 114, N = 184, 196 and Z = 164, N = 318) in late sixties by the Frankfurt school played a key role in extending the periodic table of elements up to atomic number 118. Similarly, the demonstration that nuclear matter can be compressed 510 times of its original volume by nuclear shock waves, produced during heavy ion collision, led to the production of singleand double-lambda hypernuclei, as well as anti-matter nuclei. Recent observation of antihypertriton—comprising an antiproton, an antineutron, and an antilambda hyperon, by the STAR collaboration has now made it possible to envision a 3-dimensional nuclear chart of hypernuclei. My own interest in superheavy and hypernuclei was shaped from my first meeting with Walter Greiner at the International Conference on Atomic and Nuclear clusters held at Santorini, Greece in 1993. I will present a brief summary of these exciting developments, including some of our own work. Professor Greiner’s vision, enthusiasm, and encouragement touched many lives and I was one of those privileged ones.
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Stone J, Guichon P, Thomas A. Superheavy Nuclei in the Quark-Meson-Coupling Model. EPJ WEB OF CONFERENCES 2017. [DOI: 10.1051/epjconf/201716300057] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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In search for “magic” nuclei, theory catches up to experiments. Proc Natl Acad Sci U S A 2017; 114:5060-5062. [DOI: 10.1073/pnas.1703620114] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
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Nagame Y, Kratz JV, Schädel M. Chemical properties of rutherfordium (Rf) and dubnium (Db) in the aqueous phase. EPJ WEB OF CONFERENCES 2016. [DOI: 10.1051/epjconf/201613107007] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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Rudolph D, Forsberg U, Sarmiento L, Golubev P, Fahlander C. Superheavy-element spectroscopy: Correlations along element 115 decay chains. EPJ WEB OF CONFERENCES 2016. [DOI: 10.1051/epjconf/201611701001] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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Silisteanu I, Anghel CI. Alpha-decay and spontaneous fission half-lives of super-heavy nuclei around the doubly magic nucleus270Hs. EPJ WEB OF CONFERENCES 2016. [DOI: 10.1051/epjconf/201610707004] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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Even J. Chemistry aided nuclear physics studies. EPJ WEB OF CONFERENCES 2016. [DOI: 10.1051/epjconf/201613107008] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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Schädel M. Chemistry of the superheavy elements. PHILOSOPHICAL TRANSACTIONS. SERIES A, MATHEMATICAL, PHYSICAL, AND ENGINEERING SCIENCES 2015; 373:rsta.2014.0191. [PMID: 25666065 DOI: 10.1098/rsta.2014.0191] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
The quest for superheavy elements (SHEs) is driven by the desire to find and explore one of the extreme limits of existence of matter. These elements exist solely due to their nuclear shell stabilization. All 15 presently 'known' SHEs (11 are officially 'discovered' and named) up to element 118 are short-lived and are man-made atom-at-a-time in heavy ion induced nuclear reactions. They are identical to the transactinide elements located in the seventh period of the periodic table beginning with rutherfordium (element 104), dubnium (element 105) and seaborgium (element 106) in groups 4, 5 and 6, respectively. Their chemical properties are often surprising and unexpected from simple extrapolations. After hassium (element 108), chemistry has now reached copernicium (element 112) and flerovium (element 114). For the later ones, the focus is on questions of their metallic or possibly noble gas-like character originating from interplay of most pronounced relativistic effects and electron-shell effects. SHEs provide unique opportunities to get insights into the influence of strong relativistic effects on the atomic electrons and to probe 'relativistically' influenced chemical properties and the architecture of the periodic table at its farthest reach. In addition, they establish a test bench to challenge the validity and predictive power of modern fully relativistic quantum chemical models.
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Affiliation(s)
- Matthias Schädel
- Advanced Science Research Center, Japan Atomic Energy Agency, Tokai, Japan GSI Helmholtzzentrum für Schwerionenforschung mbH, Darmstadt, Germany
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Yanez R, Loveland W, Yao L, Barrett JS, Zhu S, Back BB, Khoo TL, Alcorta M, Albers M. Measurement of the survival probabilities for hot fusion reactions. PHYSICAL REVIEW LETTERS 2014; 112:152702. [PMID: 24785034 DOI: 10.1103/physrevlett.112.152702] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/17/2014] [Indexed: 06/03/2023]
Abstract
We have studied the fission-neutron emission competition in highly excited (274)Hs (Z=108) (where the fission barrier is due to shell effects) formed by a hot fusion reaction. Matching cross bombardments ((26)Mg+(248)Cm and (25)Mg+(248)Cm) were used to identify the properties of first chance fission of (274)Hs. A Harding-Farley analysis of the fission neutrons emitted in the (25)Mg,26+(248)Cm was performed to identify the prescission and postscission components of the neutron multiplicities in each system. (Γn/Γt) for the first chance fission of (274)Hs (E*=63 MeV) is 0.89±0.13; i.e., ∼90% of the highly excited nuclei survive. The high value of that survival probability is due to dissipative effects during deexcitation. A proper description of the survival probabilities of excited superheavy nuclei formed in hot fusion reactions requires consideration of both dynamic and static (shell-related) effects.
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Affiliation(s)
- R Yanez
- Department of Chemistry, Oregon State University, Corvallis, Oregon 97331, USA
| | - W Loveland
- Department of Chemistry, Oregon State University, Corvallis, Oregon 97331, USA
| | - L Yao
- Department of Chemistry, Oregon State University, Corvallis, Oregon 97331, USA
| | - J S Barrett
- Department of Chemistry, Oregon State University, Corvallis, Oregon 97331, USA
| | - S Zhu
- Physics Division, Argonne National Laboratory, Argonne, Illinois 60439, USA
| | - B B Back
- Physics Division, Argonne National Laboratory, Argonne, Illinois 60439, USA
| | - T L Khoo
- Physics Division, Argonne National Laboratory, Argonne, Illinois 60439, USA
| | - M Alcorta
- Physics Division, Argonne National Laboratory, Argonne, Illinois 60439, USA
| | - M Albers
- Physics Division, Argonne National Laboratory, Argonne, Illinois 60439, USA
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Yakushev A, Gates JM, Türler A, Schädel M, Düllmann CE, Ackermann D, Andersson LL, Block M, Brüchle W, Dvorak J, Eberhardt K, Essel HG, Even J, Forsberg U, Gorshkov A, Graeger R, Gregorich KE, Hartmann W, Herzberg RD, Hessberger FP, Hild D, Hübner A, Jäger E, Khuyagbaatar J, Kindler B, Kratz JV, Krier J, Kurz N, Lommel B, Niewisch LJ, Nitsche H, Omtvedt JP, Parr E, Qin Z, Rudolph D, Runke J, Schausten B, Schimpf E, Semchenkov A, Steiner J, Thörle-Pospiech P, Uusitalo J, Wegrzecki M, Wiehl N. Superheavy element flerovium (element 114) is a volatile metal. Inorg Chem 2014; 53:1624-9. [PMID: 24456007 DOI: 10.1021/ic4026766] [Citation(s) in RCA: 99] [Impact Index Per Article: 9.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
The electron shell structure of superheavy elements, i.e., elements with atomic number Z ≥ 104, is influenced by strong relativistic effects caused by the high Z. Early atomic calculations on element 112 (copernicium, Cn) and element 114 (flerovium, Fl) having closed and quasi-closed electron shell configurations of 6d(10)7s(2) and 6d(10)7s(2)7p1/2(2), respectively, predicted them to be noble-gas-like due to very strong relativistic effects on the 7s and 7p1/2 valence orbitals. Recent fully relativistic calculations studying Cn and Fl in different environments suggest them to be less reactive compared to their lighter homologues in the groups, but still exhibiting a metallic character. Experimental gas-solid chromatography studies on Cn have, indeed, revealed a metal-metal bond formation with Au. In contrast to this, for Fl, the formation of a weak bond upon physisorption on a Au surface was inferred from first experiments. Here, we report on a gas-solid chromatography study of the adsorption of Fl on a Au surface. Fl was produced in the nuclear fusion reaction (244)Pu((48)Ca, 3-4n)(288,289)Fl and was isolated in-flight from the primary (48)Ca beam in a physical recoil separator. The adsorption behavior of Fl, its nuclear α-decay product Cn, their lighter homologues in groups 14 and 12, i.e., Pb and Hg, and the noble gas Rn were studied simultaneously by isothermal gas chromatography and thermochromatography. Two Fl atoms were detected. They adsorbed on a Au surface at room temperature in the first, isothermal part, but not as readily as Pb and Hg. The observed adsorption behavior of Fl points to a higher inertness compared to its nearest homologue in the group, Pb. However, the measured lower limit for the adsorption enthalpy of Fl on a Au surface points to the formation of a metal-metal bond of Fl with Au. Fl is the least reactive element in the group, but still a metal.
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Wittwer D, Dressler R, Eichler R, Gäggeler HW, Türler A. Prediction of the thermal release of transactinide elements (112 ≤ Z ≤ 116) from metals. RADIOCHIM ACTA 2013. [DOI: 10.1524/ract.2013.2027] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
Abstract
Metallic catcher foils have been investigated on their thermal release capabilities for future superheavy element studies. These catcher materials shall serve as connection between production and chemical investigation of superheavy elements (SHE) at vacuum conditions. The diffusion constants and activation energies of diffusion have been extrapolated for various catcher materials using an atomic volume based model. Release rates can now be estimated for predefined experimental conditions using the determined diffusion values. The potential release behavior of the volatile SHE Cn (E112), E113, Fl (E114), E115, and Lv (E116) from polycrystalline, metallic foils of Ni, Y, Zr, Nb, Mo, Hf, Ta, and W is predicted. Example calculations showed that Zr is the best suited material in terms of on-line release efficiency and long-term operation stability. If higher temperatures up to 2773 K are applicable, tungsten is suggested to be the material of choice for such experiments.
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Türler A, Pershina V. Advances in the Production and Chemistry of the Heaviest Elements. Chem Rev 2013; 113:1237-312. [DOI: 10.1021/cr3002438] [Citation(s) in RCA: 170] [Impact Index Per Article: 15.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Affiliation(s)
- Andreas Türler
- Laboratory
of Radiochemistry
and Environmental Chemistry, Department of Chemistry and Biochemistry, University of Bern, Freiestrasse 3, CH-3012 Bern, Switzerland
- Laboratory of Radiochemistry
and Environmental Chemistry, Department Biology and Chemistry, Paul Scherrer Institute, CH-5232 Villigen PSI, Switzerland
| | - Valeria Pershina
- GSI Helmholtzzentrum für Schwerionenforschung GmbH, Planckstrasse
1, D-64291 Darmstadt, Germany
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Minaya Ramirez E, Ackermann D, Blaum K, Block M, Droese C, Düllmann CE, Dworschak M, Eibach M, Eliseev S, Haettner E, Herfurth F, Heßberger FP, Hofmann S, Ketelaer J, Marx G, Mazzocco M, Nesterenko D, Novikov YN, Plaß WR, Rodríguez D, Scheidenberger C, Schweikhard L, Thirolf PG, Weber C. Direct mapping of nuclear shell effects in the heaviest elements. Science 2012; 337:1207-10. [PMID: 22878498 DOI: 10.1126/science.1225636] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Abstract
Quantum-mechanical shell effects are expected to strongly enhance nuclear binding on an "island of stability" of superheavy elements. The predicted center at proton number Z = 114, 120, or 126 and neutron number N = 184 has been substantiated by the recent synthesis of new elements up to Z = 118. However, the location of the center and the extension of the island of stability remain vague. High-precision mass spectrometry allows the direct measurement of nuclear binding energies and thus the determination of the strength of shell effects. Here, we present such measurements for nobelium and lawrencium isotopes, which also pin down the deformed shell gap at N = 152.
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Even J, Yakushev A, Düllmann CE, Dvorak J, Eichler R, Gothe O, Hild D, Jäger E, Khuyagbaatar J, Kratz JV, Krier J, Niewisch L, Nitsche H, Pysmenetska I, Schädel M, Schausten B, Türler A, Wiehl N, Wittwer D. Rapid Synthesis of Radioactive Transition-Metal Carbonyl Complexes at Ambient Conditions. Inorg Chem 2012; 51:6431-3. [DOI: 10.1021/ic300305m] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Julia Even
- Institute for Nuclear
Chemistry, Johannes Gutenberg University Mainz, D-55099 Mainz, Germany
- SHE Chemistry Research Section, Helmholtz Institute Mainz, D-55099 Mainz, Germany
| | - Alexander Yakushev
- SHE Chemistry Department, GSI Helmholtzzentrum für Schwerionenforschung GmbH, D-64291 Darmstadt,
Germany
| | - Christoph E. Düllmann
- Institute for Nuclear
Chemistry, Johannes Gutenberg University Mainz, D-55099 Mainz, Germany
- SHE Chemistry Research Section, Helmholtz Institute Mainz, D-55099 Mainz, Germany
- SHE Chemistry Department, GSI Helmholtzzentrum für Schwerionenforschung GmbH, D-64291 Darmstadt,
Germany
| | - Jan Dvorak
- SHE Chemistry Research Section, Helmholtz Institute Mainz, D-55099 Mainz, Germany
| | - Robert Eichler
- Laboratory for
Radio- and Environmental
Chemistry, Paul Scherrer Institute, CH-5232
Villigen PSI, Switzerland
| | - Oliver Gothe
- Department of Chemistry, University of California at Berkeley, California 94720-1460, United
States
| | - Daniel Hild
- Institute for Nuclear
Chemistry, Johannes Gutenberg University Mainz, D-55099 Mainz, Germany
| | - Egon Jäger
- SHE Chemistry Department, GSI Helmholtzzentrum für Schwerionenforschung GmbH, D-64291 Darmstadt,
Germany
| | - Jadambaa Khuyagbaatar
- SHE Chemistry Research Section, Helmholtz Institute Mainz, D-55099 Mainz, Germany
- SHE Chemistry Department, GSI Helmholtzzentrum für Schwerionenforschung GmbH, D-64291 Darmstadt,
Germany
| | - Jens V. Kratz
- Institute for Nuclear
Chemistry, Johannes Gutenberg University Mainz, D-55099 Mainz, Germany
| | - Jörg Krier
- SHE Chemistry Department, GSI Helmholtzzentrum für Schwerionenforschung GmbH, D-64291 Darmstadt,
Germany
| | - Lorenz Niewisch
- Institute for Nuclear
Chemistry, Johannes Gutenberg University Mainz, D-55099 Mainz, Germany
| | - Heino Nitsche
- Department of Chemistry, University of California at Berkeley, California 94720-1460, United
States
| | - Inna Pysmenetska
- Institute for Nuclear
Chemistry, Johannes Gutenberg University Mainz, D-55099 Mainz, Germany
- SHE Chemistry Department, GSI Helmholtzzentrum für Schwerionenforschung GmbH, D-64291 Darmstadt,
Germany
| | - Matthias Schädel
- SHE Chemistry Department, GSI Helmholtzzentrum für Schwerionenforschung GmbH, D-64291 Darmstadt,
Germany
- Advanced Science
Research Center, Japan Atomic Energy Agency, Tokai, Ibaraki 319-1195,
Japan
| | - Brigitta Schausten
- SHE Chemistry Department, GSI Helmholtzzentrum für Schwerionenforschung GmbH, D-64291 Darmstadt,
Germany
| | - Andreas Türler
- Laboratory for
Radio- and Environmental
Chemistry, Paul Scherrer Institute, CH-5232
Villigen PSI, Switzerland
- Department of Chemistry
and Biochemistry, University of Berne, CH-3012 Berne, Switzerland
| | - Norbert Wiehl
- Institute for Nuclear
Chemistry, Johannes Gutenberg University Mainz, D-55099 Mainz, Germany
| | - David Wittwer
- Laboratory for
Radio- and Environmental
Chemistry, Paul Scherrer Institute, CH-5232
Villigen PSI, Switzerland
- Department of Chemistry
and Biochemistry, University of Berne, CH-3012 Berne, Switzerland
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Abstract
Abstract
Fast on-line gas chemical separations of Hs (hassium, element 108) in the form of HsO4 were applied to investigate the reactions 26Mg + 248Cm and 36S + 238U. In an experiment at the gas-filled separator DGFRS the reaction 48Ca + 226Ra was studied. In all cases the product of complete nuclear fusion is 274Hs*. For the first time, the new nuclide 270Hs was produced in the 4n evaporation channel and its decay properties investigated. The nuclide 270Hs was predicted by microscopic-macroscopic calculations to be a deformed doubly magic nucleus and its decay properties are therefore of special interest to theory. Also, much more detailed information was gained on the decay of 269Hs and its daughters, which led to a new assignment of decay properties of the daughter nuclides 265Sg and 261Rf. There is evidence fo r isomeric states in 265Sg and 261Rf, while 266Sg is not an alpha-particle emitter as believed previously, but decays by spontaneous fission (SF) with a rather short half-life. Also, interesting features of the used reaction 26Mg + 248Cm led to the discovery of the nucleus 271Hs in the same experiments. An investigation of the influence of the Q-value on the fusion reaction in relation to the location of the fusion barrier showed, that the high binding energy of 48Ca largely compensates for the lower fusion probability compared to more asymmetric reactions, while 36S is not as promising as a projectile.
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Abstract
Abstract
In recent years, significant progress in the field of superheavy element research has been achieved thanks to a novel combination of techniques from different fields. This “physical preseparation” approach includes the coupling of an ancillary setup – typically a chemistry apparatus or a counting setup – to a physical recoil separator. This latter preseparator removes unwanted nuclear reaction products as well as the intense heavy-ion beam associated with superheavy element experiments and thus isolates the evaporation residues of the nuclear fusion reactions. These are guided to the separators's focal plane, where they are extracted and available for further transport to external setups, e.g., by a gas-jet. In this overview, the development of physical preseparation is described, and experimental results from nuclear chemistry and physics that were achieved with “preseparated” isotopes are summarized, with an emphasis on results relevant for superheavy element research. The covered topics range from chemical studies in the liquid as well as in the gas phase, the measurement of nuclear decay properties and of atomic masses. Preseparation was already shown to be a very powerful approach in these studies and promises to allow further progress in superheavy element research.
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Abstract
Abstract
The experimental techniques developed to perform rapid chemical separations of the heaviest elements in the aqueous phase are presented. In general, these include transport of the nuclear reaction products to a separation device by the gas-jet technique and dissolution in an aqueous solution containing inorganic ligands for complex formation. The complexes are chemically characterized by a partition method which can be liquid–liquid extraction, ion-exchange- or reversed-phase extraction chromatography. The separated fractions are quickly evaporated to dryness for the preparation of samples for α-particle spectroscopy. Comments are given on the special situation in which chemistry has to be studied with single atoms. Theoretical predictions of chemical properties are compared to the presently known chemical behaviour of rutherfordium, Rf (element 104), dubnium, Db (element 105), seaborgium, Sg (element 106), and hassium, Hs (element 108) and to that of their lighter homologs in the Periodic Table in order to assess the role of relativistic effects in the chemistry of the heaviest elements.
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Düllmann CE. Superheavy elements at GSI: a broad research program with element 114 in the focus of physics and chemistry. ACTA ACUST UNITED AC 2011. [DOI: 10.1524/ract.2011.1842] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
Abstract
Studies of the superheavy elements form one of the pillars of the GSI research program. A unique combination of experimental facilities is installed at the GSI. Various topics, ranging from the synthesis of new elements, spectroscopy experiments to study the nuclear structures of the heaviest nuclei, highly accurate mass measurements beyond uranium, to chemical investigations of elements around element 114 and the synthesis of novel chemical superheavy element compound classes are being studied. This is complemented by fully relativistic quantum chemical calculations. As a recent highlight, the 244Pu(48Ca,3–4n)288,289114 reaction was studied, leading to the observation of element 114 at the new gas-filled recoil separator TASCA.
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Ellison PA, Gregorich KE, Berryman JS, Bleuel DL, Clark RM, Dragojević I, Dvorak J, Fallon P, Fineman-Sotomayor C, Gates JM, Gothe OR, Lee IY, Loveland WD, McLaughlin JP, Paschalis S, Petri M, Qian J, Stavsetra L, Wiedeking M, Nitsche H. New superheavy element isotopes: ²⁴²Pu(⁴⁸Ca,5n) ²⁸⁵114. PHYSICAL REVIEW LETTERS 2010; 105:182701. [PMID: 21231101 DOI: 10.1103/physrevlett.105.182701] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/23/2010] [Indexed: 05/30/2023]
Abstract
The new, neutron-deficient, superheavy element isotope ²⁸⁵114 was produced in ⁴⁸Ca irradiations of ²⁴²Pu targets at a center-of-target beam energy of 256 MeV (E*=50 MeV). The α decay of ²⁸⁵114was followed by the sequential α decay of four daughter nuclides, 281Cn, 277Ds, 273Hs, and 269Sg. 265Rf was observed to decay by spontaneous fission. The measured α-decay Q values were compared with those from a macroscopic-microscopic nuclear mass model to give insight into superheavy element shell effects. The²⁴²Pu (⁴⁸Ca,5n²)²⁸⁵114 cross section was 0.6(-0.5)+0.9 pb.
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Affiliation(s)
- P A Ellison
- Department of Chemistry, University of California, Berkeley, CA 94720, USA
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Düllmann CE, Schädel M, Yakushev A, Türler A, Eberhardt K, Kratz JV, Ackermann D, Andersson LL, Block M, Brüchle W, Dvorak J, Essel HG, Ellison PA, Even J, Gates JM, Gorshkov A, Graeger R, Gregorich KE, Hartmann W, Herzberg RD, Hessberger FP, Hild D, Hübner A, Jäger E, Khuyagbaatar J, Kindler B, Krier J, Kurz N, Lahiri S, Liebe D, Lommel B, Maiti M, Nitsche H, Omtvedt JP, Parr E, Rudolph D, Runke J, Schausten B, Schimpf E, Semchenkov A, Steiner J, Thörle-Pospiech P, Uusitalo J, Wegrzecki M, Wiehl N. Production and decay of element 114: high cross sections and the new nucleus 277Hs. PHYSICAL REVIEW LETTERS 2010; 104:252701. [PMID: 20867370 DOI: 10.1103/physrevlett.104.252701] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/22/2009] [Indexed: 05/29/2023]
Abstract
The fusion-evaporation reaction 244Pu(48Ca,3-4n){288,289}114 was studied at the new gas-filled recoil separator TASCA. Thirteen correlated decay chains were observed and assigned to the production and decay of {288,289}114. At a compound nucleus excitation energy of E{*}=39.8-43.9 MeV, the 4n evaporation channel cross section was 9.8{-3.1}{+3.9} pb. At E^{*}=36.1-39.5 MeV, that of the 3n evaporation channel was 8.0{-4.5}{+7.4} pb. In one of the 3n evaporation channel decay chains, a previously unobserved α branch in 281Ds was observed (probability to be of random origin from background: 0.1%). This α decay populated the new nucleus 277Hs, which decayed by spontaneous fission after a lifetime of 4.5 ms.
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Affiliation(s)
- Ch E Düllmann
- GSI Helmholtzzentrum für Schwerionenforschung GmbH, 64291 Darmstadt, Germany.
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Tatsumi K, Corish J. Name and symbol of the element with atomic number 112 (IUPAC Recommendations 2010). PURE APPL CHEM 2010. [DOI: 10.1351/pac-rec-09-08-20] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
A joint IUPAC/IUPAP Working Party (JWP) has confirmed the discovery of the element with atomic number 112. In accord with IUPAC procedures, the discoverers proposed a name, copernicium, and symbol, Cn, for the element. The IUPAC Inorganic Chemistry Division Committee recommended this proposal for acceptance, and it has now been approved by the IUPAC Bureau as delegated to act by the IUPAC Council meeting on 12 August 2007.
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Affiliation(s)
- Kazuyuki Tatsumi
- 1Research Center for Materials Science, Nagoya University, Furo-cho, Chikusa-ku, Nagoya 464-8602, Japan
| | - John Corish
- 2School of Chemistry, Trinity College, University of Dublin, Dublin 2, Ireland
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Abstract
The IUPAC/IUPAP Joint Working Party (JWP) on the priority of claims to the discovery of new elements has reviewed the relevant literature pertaining to several claims. In accordance with the criteria for the discovery of elements previously established by the 1992 IUPAC/IUPAP Transfermium Working Group (TWG), and reiterated by the 1999 and 2003 IUPAC/IUPAP JWPs, it was determined that the 1996 and 2002 claims by the Hofmann et al. research collaborations for the discovery of the element with atomic number 112 at Gesellschaft für Schwerionenforschung (GSI) share in the fulfillment of those criteria. A synopsis of Z = 112 experiments and related efforts is presented. A subsequent report will address identification of higher-Z elements including those of odd atomic number.
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Düllmann CE, Gregorich KE, Pang GK, Dragojevic I, Eichler R, Folden III C, Garcia MA, Gates JM, Hoffman D, Nelson SL, Sudowe R, Nitsche H. Gas chemical investigation of hafnium and zirconium complexes with hexafluoroacetylacetone using preseparated short-lived radioisotopes. RADIOCHIM ACTA 2009. [DOI: 10.1524/ract.2009.1630] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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Dvorak J, Brüchle W, Chelnokov M, Düllmann CE, Dvorakova Z, Eberhardt K, Jäger E, Krücken R, Kuznetsov A, Nagame Y, Nebel F, Nishio K, Perego R, Qin Z, Schädel M, Schausten B, Schimpf E, Schuber R, Semchenkov A, Thörle P, Türler A, Wegrzecki M, Wierczinski B, Yakushev A, Yeremin A. Observation of the 3n evaporation channel in the complete hot-fusion reaction 26Mg + 248Cm leading to the new superheavy nuclide 271Hs. PHYSICAL REVIEW LETTERS 2008; 100:132503. [PMID: 18517941 DOI: 10.1103/physrevlett.100.132503] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/31/2007] [Indexed: 05/26/2023]
Abstract
The analysis of a large body of heavy ion fusion reaction data with medium-heavy projectiles (6 < or = Z < or = 18) and actinide targets suggests a disappearance of the 3n exit channel with increasing atomic number of the projectile. Here, we report a measurement of the excitation function of the reaction (248)Cm ((26)Mg,xn)(274-x)Hs and the observation of the new nuclide (271)Hs produced in the 3n evaporation channel at a beam energy well below the Bass fusion barrier with a cross section comparable to the maxima of the 4n and 5n channels. This indicates the possible discovery of new neutron-rich transactinide nuclei using relatively light heavy ion beams of the most neutron-rich stable isotopes and actinide targets.
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Affiliation(s)
- J Dvorak
- Technische Universität München, D-85748 Garching, Germany
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Hummrich H, Banik NL, Breckheimer M, Brüchle W, Buda R, Feist F, Jäger E, Kratz JV, Kuczewski B, Liebe D, Niewisch L, Schädel M, Schausten B, Schimpf E, Wiehl N. Electrodeposition methods in superheavy element chemistry. RADIOCHIM ACTA 2008. [DOI: 10.1524/ract.2008.1473] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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