Chemical Properties Of Superheavy Elements Research Articles

Simulation of ion optics in a gas-filled solenoid GASSOL

The results of simulation of ion optics in a gas-filled solenoid GASSOL are presented. The principle of operation of the gas-filled solenoid is described and a method for implementing a separation system based on a static turbine is proposed. On the basis of the simulation results, the potential capabilities of the setup for studying the chemical properties of superheavy elements from Fl to Ts are demonstrated.

Rapid extraction of short-lived isotopes from a buffer gas cell for use in gas-phase chemistry experiments. Part I: Off-line studies with 219Rn and 221Fr

To study the chemical properties of the heaviest elements, a fast and efficient stopping and extraction of the highly energetic residues from heavy ion fusion reactions into the chemistry setup is essential. Currently used techniques like Recoil Transfer Chambers (RTC) relying on gas flow extraction provide high efficiencies for chemically non-reactive volatile species, but operate at extraction times textr of about 0.5s or more. Buffer Gas Cells (BGC) with electric and Radio-Frequency (RF) fields offer much faster extraction times. Here, we demonstrate the successful coupling of a BGC to a gas chromatography setup as is used for studies of chemical properties of superheavy elements. Using 223Ra and 225Ac recoil ion sources providing 219Rn and 221Fr ions for off-line tests, an extraction time textr = 55(4)ms and an extraction efficiency of 35(3)% were achieved for the non-reactive 219Rn, while 221Fr was retained. The results show a BGC-based setup to be suitable for gas-phase experiments with short-lived volatile transactinide elements like Cn and Fl with half-lives substantially below 1s.

Production and study of chemical properties of superheavy elements

Abstract Some highlight examples on the study of production and chemical properties of heaviest elements carried out mostly at GSI Darmstadt are presented. They focus on the production of some of the heaviest known elements (114Fl, 115Mc, and 117Mc), studies of non-fusion reactions, and on chemical studies of 114Fl. This is the heaviest element, for which chemical studies have been performed to date.

Simulation of chemical properties of superheavy elements from the island of stability

The review covers main methods of the first-principle based electronic structure simulation used for the prediction of the properties of superheavy element atoms and compounds. The areas of applicability of these methods and the principal and practical limitations of their accuracy are analyzed. The regularities in the changes of the chemical properties on going from superheavy elements to their closest homologs are discussed.

Rapid Synthesis of Radioactive Transition-Metal Carbonyl Complexes at Ambient Conditions

Carbonyl complexes of radioactive transition metals can be easily synthesized with high yields by stopping nuclear fission or fusion products in a gas volume containing CO. Here, we focus on Mo, W, and Os complexes. The reaction takes place at pressures of around 1 bar at room temperature, i.e., at conditions that are easy to accommodate. The formed complexes are highly volatile. They can thus be transported within a gas stream without major losses to setups for their further investigation or direct use. The rapid synthesis holds promise for radiochemical purposes and will be useful for studying, e.g., chemical properties of superheavy elements.

Detecting system of the setup for studying chemical properties of superheavy elements using the gas chemistry techniques

A setup for studying the physicochemical properties of superheavy elements in experiments involving gas transport systems is described. The setup is composed of four detecting modules with semiconductor detectors; systems of data acquisition, storage, and processing; a cooling system for semiconductor detectors; and a vacuum system. In each detecting module, there are two oppositely located four-strip semiconductor detectors. The detecting system is capable of detecting with a high efficiency α particles and spontaneous fission fragments produced in decays of superheavy elements.

Heaviest Nuclei

Experimental results on the synthesis of the heaviest nuclides produced in reactions induced by 48Ca -projectiles are presented. The decay properties of the new nuclei confirm the theoretical predictions about existence of new nuclear shells and the “islands of stability” in the region of very heavy nuclei. First experiments aimed to study the chemical properties of superheavy elements are reported also.

Radiochemical Investigations at the FLNR

The paper considers a programme of development of radiochemical investigations at the FLNR in the light of recent results on the synthesis of isotopes of elements 108–116 in reactions between Ca and U, Pu, Pu, Cm. Three main lines of the investigation are discussed: chemical identification and study of chemical properties of superheavy elements (SHE), on-line mass separation for the detection of SHE, and the setting of new experiments on the search of SHE in Nature.

Theoretical chemistry of superheavy elements E116 and E114

RECENT evidence1 for the presence of primordial superheavy elements 126, 124, 116 and possibly 114 in microscopic crystalline monazite inclusions in biotite micas raises several interesting questions. Earlier work2,3 suggested reasons why E124 and E126, the homologues of U and Pu, respectively, might occur in such an environment, but gives little information about E116. Better information on both E114 (eka–Pb) and E116 (eka–Po) could enable us to see why they might occur in these minerals and help suggest methods of concentration. At present, ab initio relativistic structure calculations for molecules containing superheavy elements are not feasible. We have developed techniques, however, for studying the structure of heavy atoms and ions using the multi-configuration Dirac–Fock (MCDF) relativistic self-consistent field method4; this is a considerable advance on the single configuration Dirac–Fock or Dirac–Slater techniques previously available2,3. Applications of the MCDF method to atoms and ions of Ba, Hf (Ref. 4), Bi and U, for example, have yielded good ionisation potentials and energy spectra, mainly due to the way in which relativistic effects, which increase dramatically in size with atomic number2–4, are handled. These effects make it difficult to predict some chemical properties of superheavy elements by extrapolation from the Periodic Table. We use here, therefore, the results of MCDF calculations of some properties to estimate the heat of formation of simple compounds of E114 and E116 with the simple ionic model5 and with Pauling's semi-empirical valence-bond resonance model6, to acquire insight into the chemistry of these elements.

Chemical and physical properties of superheavy elements

A knowledge of the physical and chemical properties of superheavy elements is expected to be of great value for the detection of these elements, owing to the need for chemical separation in their isolation and identification. The methods for predicting their electronic structures, expected trends in their chemical and physical properties and the results of such predictions for the individual superheavy elements are reviewed. The periodic table is extended up to element 172.