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Journal Articles

Online chemical adsorption studies of Hg, Tl, and Pb on SiO$$_{2}$$ and Au surfaces in preparation for chemical investigations on Cn, Nh, and Fl at TASCA

Lens, L.*; Yakushev, A.*; D$"u$llmann, Ch. E.*; Asai, Masato; Ballof, J.*; Block, M.*; David, H. M.*; Despotopulos, J.*; Di Nitto, A.*; Eberhardt, K.*; et al.

Radiochimica Acta, 106(12), p.949 - 962, 2018/12

 Times Cited Count:2 Percentile:33.17(Chemistry, Inorganic & Nuclear)

Online gas-solid adsorption studies with single atom quantities of Hg, Tl, and Pb on SiO$$_{2}$$ and Au surfaces were carried out using short-lived radioisotopes with half-lives in the range of 4-49 s. This is a model study to measure adsorption enthalpies of superheavy elements Cn, Nh, and Fl. The short-lived isotopes were produced and separated by the gas-filled recoil separator TASCA at GSI. The products were stopped in He gas, and flushed into gas chromatography columns made of Si detectors whose surfaces were covered by SiO$$_{2}$$ or Au. The short-lived Tl and Pb were successfully measured by the Si detectors with the SiO$$_{2}$$ surface at room temperature. On the other hand, the Hg did not adsorb on the SiO$$_{2}$$ surface, but adsorbed on the Au surface. The results demonstrated that the adsorption properties of short-lived Hg, Tl, and Pb could be studied with this setup, and that this method is applicable to the experiment for Cn, Nh, and Fl.

Journal Articles

Measurement of the first ionization potential of astatine by laser ionization spectroscopy

Rothe, S.*; Andreyev, A. N.*; Antalic, S.*; Borschevsky, A.*; Capponi, L.*; Cocolios, T. E.*; De Witte, H.*; Eliav, E.*; Fedorov, D. V.*; Fedosseev, V. N.*; et al.

Nature Communications (Internet), 4, p.1835_1 - 1835_6, 2013/05

 Times Cited Count:71 Percentile:94.96(Multidisciplinary Sciences)

Journal Articles

Sulfate complexation of element 104, Rf, in H$$_{2}$$SO$$_{4}$$/HNO$$_{3}$$ mixed solution

Li, Z.*; Toyoshima, Atsushi; Asai, Masato; Tsukada, Kazuaki; Sato, Tetsuya; Sato, Nozomi; Kikuchi, Takahiro; Nagame, Yuichiro; Sch$"a$del, M.; Pershina, V.*; et al.

Radiochimica Acta, 100(3), p.157 - 164, 2012/03

 Times Cited Count:10 Percentile:65.97(Chemistry, Inorganic & Nuclear)

Journal Articles

Fluorido complex formation of element 104, rutherfordium (Rf)

Ishii, Yasuo; Toyoshima, Atsushi; Tsukada, Kazuaki; Asai, Masato; Li, Z.*; Nagame, Yuichiro; Miyashita, Sunao*; Mori, Tomotaka*; Suganuma, Hideo*; Haba, Hiromitsu*; et al.

Bulletin of the Chemical Society of Japan, 84(9), p.903 - 911, 2011/09

 Times Cited Count:15 Percentile:49.37(Chemistry, Multidisciplinary)

The cation-exchange behavior of element 104, rutherfordium (Rf), was investigated together with its lighter group-4 homologues Zr and Hf, and the tetravalent pseudo-homologue Th in HF/HNO$$_{3}$$ mixed solution. The results demonstrate that distribution coefficients ($$K_{d}$$) of Rf in HF/0.10 M HNO$$_{3}$$ decrease with increasing concentration of the fluoride ion [F$$^{-}$$], indicating the consecutive formation of fluorido complexes of Rf. We also measured the $$K_{d}$$ values of Rf and the homologues as a function of the hydrogen ion concentration [H$$^{+}$$]. The log $$K_{d}$$ values decrease linearly with an increase of log [H$$^{+}$$] with slopes between -2.1 and -2.5. This indicates that these elements are likely to form the same chemical compounds: mixture of [MF]$$^{3+}$$ and [MF$$_{2}$$]$$^{2+}$$ (M = Rf, Zr, Hf and Th) in the studied solution. It is also ascertained that sequence in the fluoride complex formation is Zr $$sim$$ Hf $$>$$ Rf $$>$$ Th.

Journal Articles

Fluoride complexation of element 104, rutherfordium (Rf), investigated by cation-exchange chromatography

Ishii, Yasuo; Toyoshima, Atsushi; Tsukada, Kazuaki; Asai, Masato; Tome, Hayato; Nishinaka, Ichiro; Nagame, Yuichiro; Miyashita, Sunao*; Mori, Tomotaka*; Suganuma, Hideo*; et al.

Chemistry Letters, 37(3), p.288 - 289, 2008/03

 Times Cited Count:18 Percentile:54.69(Chemistry, Multidisciplinary)

We have investigated cation-exchange behavior of Rf together with the lighter homologues of the group-4 elements Zr and Hf, and the tetravalent pseudo-homologue Th, in HF/HNO$$_{3}$$ solution using Automated Ion exchange separation apparatus coupled with the Detection system for Alpha spectroscopy (AIDA). The ${it K}$ $$_{d}$$ values of Zr, Hf, Th and Rf in HF/0.1 M HNO$$_{3}$$ were decreased with increasing the concentration of the fluoride ion [F$$^{-}$$], indicating the formation of the fluoride complexes. The sequence of the fluoride complexation strength is Zr $$sim$$ Hf $$>$$ Rf $$>$$ Th.

Journal Articles

Improved density functional calculations including magnetic effects for RfCl$$_{4}$$ and its homologues

Anton, J.*; Hirata, Masaru; Fricke, B.*; Pershina, V.*

Chemical Physics Letters, 380(1-2), p.95 - 98, 2003/10

 Times Cited Count:6 Percentile:19.07(Chemistry, Physical)

We use the newly developed non collinear spin polarized density functional method to describe the tetrachlorides of element Rutherfordium (Rf) and its homologues. It is the first time that a real three-dimensional molecule is described with this method. Without any additional corrections (used so far for the atomic values) we get nearly complete agreement for all homologues and thus a good prediction for the unknown value for RfCl$$_{4}$$.

Journal Articles

Total energy calculations of RfCl$$_{4}$$ and homologues in the framework of relativistic density functionaltheory

Varga, S.*; Fricke, B.*; Hirata, Masaru; Bastug, T.; Pershina, V.*; Frizsche, S.*

Journal of Chemical Physics, 104(27), p.6495 - 6498, 2000/06

no abstracts in English

Journal Articles

Chromatographic studies of rutherfordium (element 104) with tributylphosphate

Br$"u$chle, W.*; Eichler, B.*; G$"a$ggeler, H. W.*; Guenther, R.*; J$"a$ger, E.*; Jost, D.*; Kratz, J. V.*; Nagame, Yuichiro; Paulus, W.*; Pershina, V.*; et al.

Proceedings of 1st International Conference on the Chemistry and Physics of the Transactinide Elements, 3 Pages, 1999/00

no abstracts in English

Oral presentation

Chemical studies of Mo and W in preparation of a Seaborgium (Sg) reduction experiment using MDG, FEC, and SISAK

Toyoshima, Atsushi; Miyashita, Sunao*; Asai, Masato; Sato, Tetsuya; Kaneya, Yusuke; Tsukada, Kazuaki; Kitatsuji, Yoshihiro; Nagame, Yuichiro; Sch$"a$del, M.; Lerum, H. V.*; et al.

no journal, , 

To carry out a continuous reduction experiment of Sg with the low production rates and the short half-life, we are developing a new chemistry assembly consisting of a membrane degasser (MDG), a flow electrolytic column (FEC), the continuous liquid-liquid extraction apparatus, and the liquid scintillation counting system (SISAK). Recently, we have begun preparatory studies with Mo and W isotopes. Aqueous solution dissolving Mo and W was successfully separated from a carrier gas. Redox couples of Mo(VI)/Mo(V) and W(VI)/W(V) in HCl have been characterized for their macro amounts. Extraction behavior of Mo(VI) and W(VI) between toluene containing hinokitiol (HT) and HCl was successfully observed by a batch method. On-line extractions of short-lived Mo and W were also carried out using SISAK and MDG. In the symposium, our present status of the preparation with Mo and W will be presented.

Oral presentation

Electrolytic reduction studies of Mo and W towards the reduction of seaborgium

Toyoshima, Atsushi; Asai, Masato; Attallah, M. F.*; Goto, Naoya*; Gupta, N. S.*; Haba, Hiromitsu*; Huang, M.*; Kanaya, Jumpei*; Kaneya, Yusuke; Kasamatsu, Yoshitaka*; et al.

no journal, , 

Towards electrolytic reduction of Sg, batch-wise electrolytic reduction of carrier-free $$^{93m}$$Mo and $$^{176,181}$$W radiotracers was studied using a flow electrolytic column (FEC). The electrolyzed samples from a FEC were chemically analyzed by solvent extraction with TOA and HDEHP to separate and identify reduced species from the stable Mo(VI) and W(VI) ones based on their different extraction behavior. $$^{93m}$$Mo and $$^{176, 181}$$W were applied as radiotracers. We also performed cyclic voltammetry and UV/Vis absorption spectrometry of macro amounts of Mo and W in acidic solutions to obtain information on redox reactions of these elements under given conditions. In the conference, the present status of the preparatory reduction experiments with Mo and W will be presented.

Oral presentation

Electrolytic reduction of Mo and W as lighter homologues of seaborgium

Toyoshima, Atsushi; Miyashita, Sunao*; Oe, Kazuhiro*; Kitayama, Yuta*; Lerum, H. V.*; Goto, Naoya*; Kaneya, Yusuke; Komori, Yukiko*; Mitsukai, Akina*; Vascon, A.; et al.

no journal, , 

no abstracts in English

Oral presentation

Adsorption behavior of lawrencium (Lr) on a tantalum surface

Sato, Tetsuya; Kaneya, Yusuke*; Asai, Masato; Tsukada, Kazuaki; Toyoshima, Atsushi; Mitsukai, Akina*; Osa, Akihiko; Makii, Hiroyuki; Nishio, Katsuhisa; Hirose, Kentaro; et al.

no journal, , 

The ground state electronic configuration of lawrencium (Lr, Z =103) is predicted to be [Rn]$$5f^{14}7s^27p_{1/2}$$, which is different from that of the lanthanide homolog Lu [Xe]$$4f^{14}6s^25d$$ due to strong relativistic effects. According to semi-empirical considerations, volatility of Lr is expected to be higher than that of Lu. We have investigated adsorption behavior of $$^{256}$$Lr, which was produced in the reaction of $$^{249}$$Cf($$^{11}$$B, 4n), on a tantalum (Ta) metal surface using a surface ion-source installed into the isotope separator on-line (ISOL) at the JAEA tandem accelerator facility. The observed adsorption behavior of $$^{256}$$Lr was similar to those of Tb and Lu which have relatively higher adsorption enthalpy on Ta surface. It implies that Lr would have low volatility like such as Lu and Tb.

Oral presentation

Adsorption of lawrencium (Lr) on a metallic tantalum (Ta) surface

Kaneya, Yusuke*; Tomitsuka, Tomohiro; Sato, Tetsuya; Asai, Masato; Tsukada, Kazuaki; Toyoshima, Atsushi; Mitsukai, Akina; Makii, Hiroyuki; Hirose, Kentaro; Osa, Akihiko; et al.

no journal, , 

Oral presentation

Adsorption of lawrencium on a metallic tantalum surface at high temperature

Kaneya, Yusuke*; Asai, Masato; Sato, Tetsuya; Tomitsuka, Tomohiro; Tsukada, Kazuaki; Toyoshima, Atsushi; Mitsukai, Akina; Makii, Hiroyuki; Hirose, Kentaro; Osa, Akihiko; et al.

no journal, , 

To study the influence of the valence 7p$$_{1/2}$$ electronic orbital on chemical properties of lawrencium, a measurement of the adsorption enthalpy of lawrencium was carried out. A new method using a surface ionization technique coupled to an on-line isotope separator was developed, which enabled one to measure temperature dependence of lawrencium surface adsorption on a metallic tantalum surface at high temperature up to 2800 K. The temperature dependences of adsorption of lawrencium as well as various lanthanide elements were investigated with this method, and the adsorption enthalpy of lawrencium was successfully extracted.

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