Search results for "Hassium"
showing 10 items of 10 documents
FT-ICR MS studies of ion-molecule reactions of Ru+ and Os+ with oxygen
2005
Abstract The reactions of stored ruthenium and osmium cations with oxygen have been studied in a Fourier transform ion cyclotron resonance (FT-ICR) mass spectrometer. In case of osmium the reaction products OsO+ and OsO 2 + have been observed and corresponding reaction-rate constants have been determined. In addition, there is an unreactive fraction of Os+ ions due to the presence of a slightly endothermic reacting ground state. Only the excited states react with oxygen. For ruthenium no spontaneous reaction with oxygen has been observed unless the cyclotron motion of Ru+ was excited. The results are discussed with respect to a similar investigation in a Penning trap-TOF mass spectrometer […
Liquid-Phase Chemistry of Superheavy Elements
2013
An overview over the chemical separation and characterization experiments of the four transactinide elements so far studied in liquid phases, rutherfordium (Rf), dubnium (Db), seaborgium (Sg), and hassium (Hs), is presented. Results are discussed in view of the position of these elements in the Periodic Table and of their relation to theoretical predictions. Short introductions on experimental techniques in liquid-phase chemistry, specifically automated rapid chemical separation systems, are also given. Studies of nuclear properties of transactinide nuclei by chemical isolation will be mentioned. Some perspectives for further liquid-phase chemistry on heavier elements are briefly discussed.
Preparation of targets by electrodeposition for heavy element studies
2004
Abstract For heavy element studies at GSI, lanthanide and actinide targets have been prepared by molecular plating. The deposition occurs from an isopropanolic solution at 1000–1200 V with current densities of a few mA/cm 2 . Several lanthanide targets have been prepared for test experiments. With nat Gd deposited on a 10 μm thick Be backing foil a target density of 1100 μg/cm 2 could be achieved. Gd-targets were used for the production of α-emitting isotopes of Os, the homologue of hassium (Hs; Z =108), in order to develop a chemical separation procedure for Hs. 248 Cm targets with densities up to 730 μg/cm 2 have been produced for recent experiments to investigate the chemical behaviour o…
Chemical investigation of hassium (element 108).
2002
The periodic table provides a classification of the chemical properties of the elements. But for the heaviest elements, the transactinides, this role of the periodic table reaches its limits because increasingly strong relativistic effects on the valence electron shells can induce deviations from known trends in chemical properties. In the case of the first two transactinides, elements 104 and 105, relativistic effects do indeed influence their chemical properties, whereas elements 106 and 107 both behave as expected from their position within the periodic table. Here we report the chemical separation and characterization of only seven detected atoms of element 108 (hassium, Hs), which were…
Cold fusion of heavy ions paving the way to superheavy elements
2001
Abstract Significant progress has been made approaching superheavy elements. A shell-stabilized region near hassium has been discovered. Element 112 has been synthesized. Recently evidence for the creation of elements 114, 116, and 118 has been reported. The way to these superheavy nuclei was paved by the cold fusion of heavy ions. In this paper experimental methods for heavy-element research, which is essentially physics with single atoms, are presented together with recent experimental results. The observed nuclear properties are discussed in the framework of theoretical models. New instrumental developments including accelerators and radioactive beams are be addressed.
Theoretical study of the electron structure of superheavy elements with an open 6d shell: Sg, Bh, Hs, and Mt
2019
We use recently developed efficient versions of the configuration interaction method to perform {\em ab initio} calculations of the spectra of superheavy elements seaborgium (Sg, $Z=106$), bohrium (Bh, $Z=107$), hassium (Hs, $Z=108$) and meitnerium (Mt, $Z=109$). We calculate energy levels, ionization potentials, isotope shifts and electric dipole transition amplitudes. Comparison with lighter analogs reveals significant differences caused by strong relativistic effects in superheavy elements. Very large spin-orbit interaction distinguishes subshells containing orbitals with a definite total electron angular momentum $j$. This effect replaces Hund's rule holding for lighter elements.
Cross section limits for theCm248(Mg25,4n−5n)Hs268,269reactions
2009
We report on an attempt to produce and detect $^{268}\mathrm{Hs}$ and $^{269}\mathrm{Hs}$ in the nuclear fusion reaction $^{25}\mathrm{Mg}+^{248}\mathrm{Cm}$ using the gas phase chemistry apparatus COMPACT. No decay chains attributable to the decay of hassium isotopes were observed during the course of this experiment. From the nonobservation of $^{269}\mathrm{Hs}$ we derive a cross section limit of 0.4 pb (63% confidence limit) for the reaction $^{248}\mathrm{Cm}(^{25}\mathrm{Mg},4n)^{269}\mathrm{Hs}$ at a center-of-target beam energy of 140 MeV. The evaluated cross section limit for the $^{248}\mathrm{Cm}(^{25}\mathrm{Mg},5n)^{268}\mathrm{Hs}$ reaction depends on the assumed half-life of …
Microscopic description of complex nuclear decay: multimodal fission
2009
Our understanding of nuclear fission, a fundamental nuclear decay, is still incomplete due to the complexity of the process. In this paper, we describe a study of spontaneous fission using the symmetry-unrestricted nuclear density functional theory. Our results show that the observed bimodal fission can be explained in terms of pathways in multidimensional collective space corresponding to different geometries of fission products. We also predict a new phenomenon of trimodal spontaneous fission for some rutherfordium, seaborgium, and hassium isotopes.
Evidence for the formation of sodium hassate(VIII)
2004
SummaryHassium, element 108, was produced in the fusion reaction between26Mg and248Cm. The hassium recoils were oxidizedin-situto a highly volatile oxide, presumably HsO4, and were transported in a mixture of He and O2to a deposition and detection system. The latter consisted of 16 silicon PIN-photodiodes facing a layer of NaOH, which served, in the presence of a certain partial pressure of water in the transport gas, as reactive surface for the deposition of the volatile tetroxides. Six correlated α-decay chains of Hs were detected in the first 5 detectors centred around detection position 3. In analogy to OsO4, which forms Na2[OsO4(OH)2], an osmate(VIII), with aqueous NaOH, HsO4presumably…
Extraction Chromatographic Behavior of Rf, Zr, and Hf in HCl Solution with Styrenedivinylbenzene Copolymer Resin Modified by TOPO (trioctylphosphine …
2010
It is of great interest to study chemical properties of the transactinide elements with atomic numbers (Z) ≥ 104. One of the most important subjects is to establish the position of the elements at the extreme end of the periodic table. To this end we perform studies of chemical properties of these transactinides and compare them with those of their lighter homologues and with the ones expected from extrapolations in the periodic table. So far, chromatographic studies of the transactinides have provided experimental proof of placing rutherfordium (Rf, Z = 104) through hassium (Hs, Z = 108) into groups 4 to 8, respectively. 1-10 Quite recently, copernicium (Cn, Z = 112) has been shown to be a…