Benchmark study of DFT with Eu and Np Mssbauer isomer shifts using second-order Douglas-Kroll-Hess Hamiltonian

Kaneko, Masashi; Watanabe, Masayuki; Miyashita, Sunao*; Nakashima, Satoru*

Hyperfine Interactions, 239(1), p.20_1 - 20_10, 2018/12

BB2017-0056.pdf:0.5MB

https://doi.org/10.1007/s10751-018-1495-1

We optimized a mixing ratio of exchange energy between pure DFT and exact Hartree-Fock using TPSS exchange-correlation functional to estimate the accurate coordination bonds in f-block complexes by numerically benchmarking with the experimental data of Mssbauer isomer shifts for Eu and Np nuclides. Second-order Douglas-Kroll-Hess Hamiltonian with segmented all-electron relativistically contracted basis set was employed to calculate the electron densities at Eu and Np nuclei, i.e. contact densities, for each five complexes for Eu(III) and Np(IV) systems. We compared the root mean square deviation values of their isomer shifts between experiment and calculation by changing the mixing ratio of Hartree-Fock exchange parameter from 0 to 100 % at intervals of 10 %. As the result, it was indicated that the mixing ratio of 30 and 60 % for Eu and Np benchmark systems, respectively, gives the smallest deviation values. Mulliken's spin population analysis indicated that the covalency in the metal-ligand bonds for both Eu and Np complexes decreases with increasing the Hartree-Fock exchange admixture.

Estimation of / values by benchmark study of the Mssbauer Isomer shifts for Ru, Os complexes using relativistic DFT calculations

Kaneko, Masashi; Yasuhara, Hiroki*; Miyashita, Sunao*; Nakashima, Satoru*

Hyperfine Interactions, 238(1), p.36_1 - 36_9, 2017/11

AA2016-0447.pdf:0.46MB

https://doi.org/10.1007/s10751-017-1413-y

We aim to evaluate the validity of density functional calculations to the bonding property for Ru and Os complexes. We performed the benchmarking of theoretical computational method with Ru, Os Mssbauer isomer shifts. As the result, the computational values of the electron densities at nucleus position correlated with the experimental Mssbauer isomer shifts.

Roles of d- and f-orbital electrons in the complexation of Eu(III) and Am(III) ions with alkyldithiophosphinic acid and alkylphosphinic acid using scalar-relativistic DFT calculations

Kaneko, Masashi; Watanabe, Masayuki; Miyashita, Sunao*; Nakashima, Satoru*

Journal of Nuclear and Radiochemical Sciences (Internet), 17, p.9 - 15, 2017/03

http://www.radiochem.org/en/paper/JN171/jn17102.pdf

Density functional calculations were applied to the complexation of Eu(III) and Am(III) ions with phosphinic acid (O-donor) and dihiophosphinic acid (S-donor) from the viewpoint of the bonding nature of valence orbitals in metal ion. Two and four conformers for S-donor and O-donor complexes, respectively were optimized. Their stabilization energies by complex formation toward [M(HO)] were estimated. As the result, the energies reproduced the experimental Am(III)/Eu(III) selectivity that O-donor ligand preferably coordinates to Eu(III) ion, whereas S-donor ligand selectively coordinates to Am(III) ion. Focused on the bonding natures of d and f-orbital electrons, it was indicated that the d-orbital electrons in both Eu and Am complexes participate in the covalency as bonding-type nature and have the almost same contribution. Meanwhile, the contribution of the f-orbital electrons was different between Eu and Am complexes and indicated that in the case of S-donor complex, non-bonding type and bonding type contributions were observed for Eu and Am complexes, respectively and in the case of O-donor complex, bonding type and anti-bonding type contributions were observed for Eu and Am complexes, respectively. This result suggested that the bonding natures of d-orbital electrons contribute to the geometrical similarity of molecular structures for Eu and Am complexes and the bonding natures of f-orbital electrons contribute to the difference in the selectivity of Eu and Am ions.

Complex chemistry with complex compounds

Eichler, R.*; Asai, Masato; Brand, H.*; Chiera, N. M.*; Di Nitto, A.*; Dressler, R.*; Dllmann, Ch. E.*; Even, J.*; Fangli, F.*; Goetz, M.*; et al.

EPJ Web of Conferences, 131, p.07005_1 - 07005_7, 2016/12

https://doi.org/10.1051/epjconf/201613107005

In recent years gas-phase chemical studies assisted by physical pre-separation allowed for the productions and investigations of fragile single molecular species of superheavy elements. The latest highlight is the formation of very volatile hexacarbonyl compound of element 106, Sg(CO). Following this success, second-generation experiments were performed to measure the first bond dissociation energy between the central metal atom and the surrounding ligand. The method using a tubular decomposition reactor was developed and successfully applied to short-lived Mo(CO), W(CO), and Sg(CO).

Measurement of the first ionization potential of lawrencium, element 103

Sato, Tetsuya; Asai, Masato; Borschevsky, A.*; Stora, T.*; Sato, Nozomi; Kaneya, Yusuke; Tsukada, Kazuaki; Dllmann, Ch. E.*; Eberhardt, K.*; Eliav, E.*; et al.

Nature, 520(7546), p.209 - 211, 2015/04

https://doi.org/10.1038/nature14342

Ionization efficiency in a surface ionization process depends on the first ionization potential of the atom. Based on the dependence, the ionization potential of the atom can be determined. We successfully measured ionization efficiencies of lawrencium (Lr, =103) using a gas-jet coupled surface ion-source. The ionization potential of Lr has not been determined owing to its low production rate and its short half-life. Based on a relationship between the ionization efficiency and the ionization potential obtained via measurements of short-lived lanthanide isotopes, the ionization potential of Lr was determined.

Development of a He/CdI gas-jet system coupled to a surface-ionization type ion-source in JAEA-ISOL; towards determination of the first ionization potential of Lr (Z = 103)

Sato, Tetsuya; Asai, Masato; Sato, Nozomi; Tsukada, Kazuaki; Toyoshima, Atsushi; Oe, Kazuhiro*; Miyashita, Sunao*; Kaneya, Yusuke; Osa, Akihiko; Schdel, M.; et al.

Journal of Radioanalytical and Nuclear Chemistry, 303(2), p.1253 - 1257, 2015/02

https://doi.org/10.1007/s10967-014-3467-5

We have developed a surface-ionization ion-source coupled to the He/CdI gas-jet transport system for the Isotope Separator On-Line (ISOL) at the JAEA tandem accelerator for experimental determination of the first ionization potential of lawrencium (Lr, ). We performed to ionize a short-lived Lr isotope and various lanthanide isotopes. We successfully observed mass-separated ions of Lr by using our present system at the first time. The first ionization potential of Lr was evaluated based on a correlation between of effective ionization potential and ionization efficiency of short-lived lanthanide isotopes in our system.

Synthesis and detection of a Seaborgium carbonyl complex

Even, J.*; Yakushev, A.*; Dllmann, Ch. E.*; Haba, Hiromitsu*; Asai, Masato; Sato, Tetsuya; Brand, H.*; Di Nitto, A.*; Eichler, R.*; Fan, F. L.*; et al.

Science, 345(6203), p.1491 - 1493, 2014/09

https://doi.org/10.1126/science.1255720

A new superheavy element complex, a seaborgium carbonyl, has been successfully synthesized, and its adsorption property has been studied using a cryo-thermochromatography and -detection apparatus COMPACT. Nuclear reaction products of short-lived Sg preseparated with a gas-filled recoil ion separator GARIS at RIKEN were directly injected into a gas cell filled with He/CO mixture gas, and chemical reaction products of volatile carbonyl complexes were trasported to COMPACT. The Sg carbonyl complex detected with COMPACT was found to be very volatile with adsorption enthalpy of 50 kJ/mol, from which we have concluded that this complex should be a Sg hexacarbonyl Sg(CO). This is the first synthesis of organometallic compounds of transactinide elements for which only simple inorganic comounds have been synthesized so far.

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

https://doi.org/10.1246/bcsj.20110126

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 mixed solution. The results demonstrate that distribution coefficients () of Rf in HF/0.10 M HNO decrease with increasing concentration of the fluoride ion [F], indicating the consecutive formation of fluorido complexes of Rf. We also measured the values of Rf and the homologues as a function of the hydrogen ion concentration [H]. The log 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] and [MF] (M = Rf, Zr, Hf and Th) in the studied solution. It is also ascertained that sequence in the fluoride complex formation is Zr Hf Rf Th.

Cation-exchange behavior of Rf in HNO/HF mixed solution, 2

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

no journal, , 

Chemical properties of rutherfordium (Rf, the element 104) in HNO/HF mixed solutions have been investigated using cation-exchange chromatography. Distribution coefficients of Rf on the cation-exchange resin as a function of hydrofluoric-acid and nitric-acid concentrations have been measured precisely, and it was found that the strength of the fluoride complex formation of Rf is much weaker than those of lighter group 4 homologs Zr and Hf. The same result was obtained through the anion-exchange chromatography. These results enabled us to quantitatively account for the fluoride complexation of Rf.

Stability constants of minor actinides and lanthanides with dithiocarbamate

Miyashita, Sunao; Kitatsuji, Yoshihiro; Kimura, Takaumi

no journal, , 

The stability constants of trivalent minor actinides (An; Am and Cm) and lanthanides (Ln; Eu) with Ammonium pyrrolidinedithiocarbamate (APDC) in aqueous solution were investigated. The stability constants were obtained by back-extraction technique using di(2-ethylhexyl)phosphoric acid (HDEHP) as follows. Aqueous phase was acetic buffer solution from 0.02 to 0.10 mol/cm containing various concentrations of APDC. Organic phase was toluene or benzene solution containing HDEHP and trace amounts of the extracted radionuclide such as Am or Cm. Eqvolumes of the aqueous phase and the organic phase were mixed in vial and were shaken 30 minutes at 298 . The results show that minor actinides strongly interacted with dithiocarbamate. From those results, the obtained stability constants (, = 1, 2) for Am are log(Am) = 2.5 0.3, log(Am) = 4.3 0.2 at 298 .