Relativistic Effects of the Superheavy Elements

Schwerdtfeger, Peter; Seth, Michael

doi:10.1002/0470845015.cra007

Cited by 37 publications

(54 citation statements)

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“…Their nuclei exist only due to nuclear shell effects, and their electron structure is influenced by increasingly important relativistic effects. [1][2][3] Syntheses of SHE with proton number Z up to 118 have been reported. 4 Elements with Z=104-112 are members of the 6d series in the Periodic Table of the Elements.…”

Section: Introductionmentioning

confidence: 99%

Superheavy Element Flerovium (Element 114) Is a Volatile Metal

et al. 2014

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Superheavy Element Flerovium (Element 114) Is a Volatile MetalAccess to the published version may require subscription. Superheavy Element Flerovium (Element 114) is a Volatile MetalAlexander Yakushev †, , Jacklyn M. 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 quasiclosed electron shell configurations of 6d 10 7s 2 and 6d 10 7s 2 7p 1/2 , respectively, predicted them to be noble gas-like due to very strong relativistic effects on the 7s and 7p 1/2 valence orbitals. Recent fully relativistic calculations studying Cn and Fl in different environments suggest them to be less reactive compared to their lighter homologs in the groups, but still exhibiting a metallic character. Experimental gassolid 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 homologs 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 homolog 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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Section: Introductionmentioning

confidence: 99%

Superheavy Element Flerovium (Element 114) Is a Volatile Metal

et al. 2014

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“…However, many landmark accomplishments resulted from a number of new and detailed experimental findings and theoretical results over the last decade. For summaries and reviews of the theoretical work see [44][45][46][47][48][49].…”

Section: Nuclear Syntheses and Decaysmentioning

confidence: 99%

“…A detailed discussions of relativistic effects in general and specifically for SHE can be found in [82][83][84] and [44][45][46][47][48][49], respectively. The relativistic mass of the electron, m, is…”

Section: Relativistic Effectsmentioning

confidence: 99%

“…Thus, it is of great interest to study chemical properties of SHE in detail and to compare these with properties deduced from extrapolations and from modern relativistic-molecular calculations. Reviews of recent theoretical work including predictions of chemical properties can be found in [44][45][46][47][48][49]. Groundstate electronic configurations and information on oxidation states are listed in Table 1.…”

Section: Introduction and Historical Remarksmentioning

confidence: 99%

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Chemistry of superheavy elements

Schädel

2012

Radiochimica Acta

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Summary. The chemistry of superheavy elements -or transactinides from their position in the Periodic Table -is summarized. After giving an overview over historical developments, nuclear aspects about synthesis of neutron-rich isotopes of these elements, produced in hot-fusion reactions, and their nuclear decay properties are briefly mentioned. Specific requirements to cope with the one-atom-at-a-time situation in automated chemical separations and recent developments in aqueous-phase and gas-phase chemistry are presented. Exciting, current developments, first applications, and future prospects of chemical separations behind physical recoil separators ("pre-separator") are discussed in detail. The status of our current knowledge about the chemistry of rutherfordium (Rf, element 104), dubnium (Db, element 105), seaborgium (Sg, element 106), bohrium (Bh, element 107), hassium (Hs, element 108), copernicium (Cn, element 112), and element 114 is discussed from an experimental point of view. Recent results are emphasized and compared with empirical extrapolations and with fully-relativistic theoretical calculations, especially also under the aspect of the architecture of the Periodic Table.

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“…11,12 Due to strong relativistic effects, it is also known that the behavior of the SHE does not necessarily follows the known trends for lighter homologues in chemical groups, and forecasting of properties and trends based on simple extrapolations of properties of lighter homologues may result in erroneous predictions. 13 In fact, the chemistry of SHE may be a lot of different to what is known due to these strong relativistic effects 14 and perform relativistic calculations is often the only source of useful chemical information. 7 From all possible options used for the inclusion of relativistic effects, the most reliable is the 4-component relativistic method, 12,15 where the relativistic effects of interest for chemistry as spin-orbit or mass-velocity are included from the onset.…”

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confidence: 99%

Ab Initio correlated all electron Dirac-Fock calculations for eka-francium fluoride (E119F)

Miranda

Mendes

Gomes

et al. 2012

J. Braz. Chem. Soc.

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Resultados obtidos por cálculos Dirac-Fock correlacionados de 4 componentes para o fluoreto do elemento E119 (Eka-Frâncio) com base estável e precisa, livre de prolapso variacional, são reportados neste trabalho. No nível CCSD(T), a distância de equilíbrio R e , frequência harmônica w e e energia de dissociação D e são 2,432 Å, 354,97 cm -1 e 116,92 kcal mol -1 , respectivamente. Também são reportados base livre de prolapso variacional de 4 componentes para o elemento 119, uma curva analítica de energia potencial precisa e o espectro vibracional a partir dos dados obtidos no nível CCSD(T). Nossos resultados sugerem que a molécula E119F deva ser menos iônica que seus fluoretos alcalinos homólogos mais leves, em contraste com o senso químico comum baseado nas propriedades periódicas -era de se esperar nesta molécula a ligação química mais iônica possível. Também encontramos que a correção do tipo modelo de carga para negligenciar as integrais do tipo SS resulta em erros insignificantes e acelera os cálculos cerca de 3 vezes no nível CCSD(T) e cerca de 4 vezes no nível DFT/B3LYP.Results obtained with correlated 4-component Dirac-Fock calculations for element E119 (ekafrancium) fluoride with stable and accurate basis set (prolapse-free) are reported in this work. At CCSD(T) level, the equilibrium distance R e , harmonic frequency w e and dissociation energy D e are 2.432 Å, 354.97 cm -1 and 116.92 kcal mol -1 , respectively. A 4-component prolapse free basis set for E119, an accurate analytical potential energy curve and vibrational spectra from CCSD(T) data are also reported. Our results suggest that E119F should be less ionic than lighter alkaline fluoride homologues, in contrast to the common chemical belief based on periodic trends -it would be expected in this molecule the most ionic bond possible. We also found that the charge model correction to neglect SS integrals leads to negligible errors and speed up calculations close to three times at CCSD(T) level and close to 4 times at DFT/B3LYP level. Keywords: super heavy elements (SHE), 4-component relativistic molecular calculations, 4-component gaussian basis sets, relativistic effects in chemistry IntroductionThe quest for super heavy nuclei began in 1940's with the synthesis of new elements with an atomic number greater than uranium, and the search for new elements was boosted with the prediction of an "island of stability" 1 for super heavy elements (SHE) with atomic numbers 114,120 and 126. [2][3][4] Some predictions estimate half-lives for isotopes with special combination of proton and neutron numbers as long as 10 8 years, as for 290 Sg 184 . 5,6 Recently, the production of the super heavy elements 112 through 118 using "hot" fusion reactions attained special chemical interest since the reported half-lives are in order of seconds, orders of magnitude longer than those of isotopes produced by "cold" fusion reactions. In addition to short half-lives, the drawback of low production rates also makes chemical experiments expensive, difficult and hard to perfo...

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Relativistic Effects of the Superheavy Elements

Cited by 37 publications

References 142 publications

Superheavy Element Flerovium (Element 114) Is a Volatile Metal

Superheavy Element Flerovium (Element 114) Is a Volatile Metal

Chemistry of superheavy elements

Ab Initio correlated all electron Dirac-Fock calculations for eka-francium fluoride (E119F)

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