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Journal Articles

Sorption behavior of selenide on montmorillonite

Sugiura, Yuki; Tomura, Tsutomu*; Ishidera, Takamitsu; Doi, Reisuke; Francisco, P. C. M.; Shiwaku, Hideaki; Kobayashi, Toru; Matsumura, Daiju; Takahashi, Yoshio*; Tachi, Yukio

Journal of Radioanalytical and Nuclear Chemistry, 324(2), p.615 - 622, 2020/05

 Times Cited Count:2 Percentile:41(Chemistry, Analytical)

Journal Articles

Application of M$$_{V}$$-edge XANES to determination of U oxidation state in zircon

Tanaka, Kazuya; Takahashi, Yoshio*

Geochemical Journal, 53(5), p.329 - 331, 2019/00

 Times Cited Count:0 Percentile:0.01(Geochemistry & Geophysics)

We examined three natural zircon samples with different amounts of radiation doses using M$$_{V}$$-edge and L$$_{III}$$-edge U X-ray absorption near-edge structure (XANES). Analysis of XANES spectra at both M$$_{V}$$-edge and L$$_{III}$$-edge suggested that the oxidation state of U in the zircon sample with the highest radiation dose is tetravalent. The XANES spectra of the two other samples with lower radiation doses suggested a mixture of U(IV) and U(VI), while the possibility of U(V) was not excluded. This is the first work on the application of M$$_{V}$$-edge U XANES to the oxidation state of U in natural zircon.

Journal Articles

Preliminary evaluation of local structure and speciation of lanthanoids in aqueous solution, iron hydroxide, manganese dioxide, and calcite using the L$$_{3}$$-Edge X-ray absorption near edge structure spectra

Ota, Atsuyuki*; Tanaka, Kazuya; Tsuno, Hiroshi*

Journal of Physical Chemistry A, 122(41), p.8152 - 8161, 2018/10

 Times Cited Count:1 Percentile:4.52(Chemistry, Physical)

We investigated the application of L$$_{3}$$-edge XANES spectra to the local structural analysis of lanthanoids in aqueous solution, iron hydroxide, manganese dioxide, and calcium carbonate. For each lanthanoid, the full width at half maximum (FWHM) values of lanthanoid compounds roughly decreased with increasing coordination numbers. However, they did not strictly reflect the local coordination sphere of the lanthanoid complex, but were rather sensitive to their chemical forms. The relationship between the magnitude of the FWHM values was determined by the crystal field splitting or degeneracy of 5d orbitals. The systematic variation of FWHM can be explained by the ligand strength of the ligand molecules (-H$$_{2}$$O$$^{0}$$, -O$$^{-}$$, -OH$$^{-}$$, -CO$$_{3}$$$$^{2-}$$, -Cl$$^{-}$$, and -O$$^{2-}$$) that cause the crystal field splitting. Therefore, the FWHM values of L$$_{3}$$-edge XANES of lanthanoid compounds may be more useful in speciation analysis rather than structural analysis such as EXAFS.

Journal Articles

Nitrogen K-edge X-ray absorption near edge structure (XANES) spectra of purine-containing nucleotides in aqueous solution

Shimada, Hiroyuki*; Fukao, Taishi*; Minami, Hirotake*; Ukai, Masatoshi*; Fujii, Kentaro; Yokoya, Akinari; Fukuda, Yoshihiro*; Saito, Yuji

Journal of Chemical Physics, 141(5), p.055102_1 - 055102_8, 2014/08

 Times Cited Count:15 Percentile:55.71(Chemistry, Physical)

Journal Articles

Difference between Cr and Ni K-edge XANES spectra of rust layers formed on Fe-based binary alloys exposed to Cl-rich environment

Konishi, Hiroyuki; Yamashita, Masato*; Uchida, Hitoshi*; Mizuki, Junichiro

Materials Transactions, 46(1), p.136 - 139, 2005/01

 Times Cited Count:2 Percentile:26.54(Materials Science, Multidisciplinary)

The rust layer formed on weathering steel possesses a strong protective ability against corrosives in an atmosphere. This ability is related to the structure of the rust layer. The difference in the protective ability of a rust layer in a Cl-rich environment between conventional weathering steel containing Cr and advanced weathering steel containing Ni is believed to be caused by the differences in local structural and chemical properties between alloying elements, Cr and Ni, in the rust layer. In order to examine the effect of these alloying elements on the structure of the rust layer formed on steel in a Cl-rich environment, we have performed Cr and Ni K-edge X-ray absorption near-edge structure (XANES) measurements for the rust layer of Fe-Cr and Fe-Ni binary alloys exposed to a Cl-rich atmosphere using synchrotron radiation. The results of the Cr K-edge XANES measurements for the rust layer of Fe-Cr binary alloys show that the atomic geometry around Cr depends on the concentration of Cr. Therefore, it is expected that the local structure around Cr in the rust layer is unstable. On the other hand, from the results of the Ni K-edge XANES measurements for the rust layer of Fe-Ni binary alloys, Ni is considered to be positioned at a specific site in the crystal structure of a constituent of the rust layer, such as akagan$'e$ite or magnetite. As a consequence, Ni negligibly interacts with Cl$$^{-}$$ ions in the rust layer.

Journal Articles

XAFS and spectroscopic characterization for the structure and electronic structure of Ce-DMDPhPDA complexes in methanol

Yaita, Tsuyoshi; Shiwaku, Hideaki; Suzuki, Shinichi; Okamoto, Yoshihiro; Shimada, Asako*; Assefa, Z.*; Haire, R. G.*

Physica Scripta, T115, p.302 - 305, 2005/00

The structural parameter and the electronic structure of the complex between cerium and N,N'-dimethyl-N,N'-diphenylpyridine-2,6-carboxyamide(DMDPhPDA) was investigated by XAFS, photo luminescence and excitation spectra. The DMDPhPDA is one of the promising ligands for separation of trivalent actinides from lanthanides. The Ce-K XAFS spectra were measured at BL11XU of SPring-8. The bond distances between the carbonyl oxygens and cerium, and between the pyridyl nitrogen and cerium are 253pm and 264pm, respectively. The bond angle of the plane consisting of the two carbonyl oxygens and nitrogen with cerium was about 180 degree. This complex was a yellow color unique for the DMDPhPDA-lanthanide complexes. The photo absorption peak for the complex was extremely broad, and the peak position was at a higher wavenumber as compared with those for the other lanthanide complexes. The peak in the highest wavenumber of this band may be attributed to the transition between f and d orbitals, which are greatly influenced by the ligand field of the DMDPhPDA. The XANES spectrum of the cerium complex clearly showed that cerium was trivalent.

Journal Articles

EPR studies of 5-bromouracil crystal after irradiation with X rays in the bromine K-edge region

Yokoya, Akinari; Takakura, Kaoru*; Watanabe, Ritsuko; Akamatsu, Ken*; Ito, Takashi*

Radiation Research, 162(4), p.469 - 473, 2004/10

 Times Cited Count:3 Percentile:10.43(Biology)

X-ray absorption spectra from single crystals of 5-Bromouracil were measured with the transmission mode in the energy range from 13.41 to 13.50 keV using the linearly polarized synchrotron radiation (SR). A characteristic resonance structure, consisting of four peaks, was recognized in the spectra in the Br K-edge region. The intensities of these peaks were strongly dependent on the crystal rotation about the normal of the crystal b-c plane, which was set perpendicular to the X-ray beam direction. (SR X-rays are polarized in the horizontal plane.) Molecular orbital calculations indicate that these resonance peaks are associated with the transitions from the 1s electron of Br to the Br-C molecular antibonding orbitals and to a shape resonance. The observed anisotropy of each photoabsorption peak might originate from the angular dependences of these molecular orbitals.

Journal Articles

Electronic structures of ultra-thin silicon carbides deposited on graphite

Baba, Yuji; Sekiguchi, Tetsuhiro; Shimoyama, Iwao; Nath, K. G.

Applied Surface Science, 234(1-4), p.246 - 250, 2004/07

 Times Cited Count:9 Percentile:44.85(Chemistry, Physical)

no abstracts in English

Journal Articles

Element-specific and site-specific ion desorption from adsorbed molecules by deep core-level photoexcitation at the $$K$$-edges

Baba, Yuji

Low Temperature Physics, 29(3), p.228 - 242, 2003/03

 Times Cited Count:53 Percentile:52.35(Physics, Applied)

no abstracts in English

Journal Articles

Structural and electronic investigation of TbPdAl by means of EXAFS and XANES measurements

Mizumaki, Masaichiro*; Yoshii, Kenji; Kitazawa, Hideaki*; Tanida, Hajime*

Journal of Solid State Chemistry, 171(1-2), p.291 - 294, 2003/02

 Times Cited Count:5 Percentile:18.26(Chemistry, Inorganic & Nuclear)

no abstracts in English

Journal Articles

Electron paramagnetic resonance induced by K-shell resonance excitation in DNA bases in solid state

Yokoya, Akinari; Akamatsu, Ken*; Fujii, Kentaro

Nuclear Instruments and Methods in Physics Research B, 99, p.366 - 369, 2003/01

no abstracts in English

Journal Articles

X-ray absorption near edge structure of DNA bases around oxygen and nitrogen K-edge

Fujii, Kentaro; Akamatsu, Ken; Muramatsu, Yasuji; Yokoya, Akinari

Nuclear Instruments and Methods in Physics Research B, 199, p.249 - 254, 2003/01

 Times Cited Count:40 Percentile:91.77(Instruments & Instrumentation)

no abstracts in English

Journal Articles

X-ray absorption study of molten uranium chloride system

Okamoto, Yoshihiro; Akabori, Mitsuo; Ito, Akinori; Ogawa, Toru

Journal of Nuclear Science and Technology, 39(Suppl.3), p.638 - 641, 2002/11

We report local structural features of molten UCl$$_3$$ with LiCl-KCl eutectic probed by the U L$$_3$$-edge XAFS(X-ray absorption fine structure). The XAFS measurements were performed in a transmission mode at the BL27B station of the Photon Factory(High Energy Accelerator Organization, Tsukuba, JAPAN). Sample prepared by chlorination of uranium hydride and then reduction with zinc powder was sealed in a quartz cell under reduced pressure. The nearest U$$^{3+}$$-Cl$$^-$$ distance and the coordination number of Cl$$^-$$ around U$$^{3+}$$ ion were obtained by a curve fitting of the 1st shell XAFS function k$$^3$$$$chi$$(k). The pair potential in the U$$^{3+}$$-Cl$$^-$$ correlation was evaluated from XAFS simulation by combinational use of the MD and the FEFF8. In addition, valence state of uranium in the melt was evaluated by XANES(X-ray absorption near edge structure) spectra.

Journal Articles

Local electronic and geometric structures of silicon atoms implanted in graphite

Baba, Yuji; Sekiguchi, Tetsuhiro; Shimoyama, Iwao

Nuclear Instruments and Methods in Physics Research B, 194(1), p.41 - 46, 2002/07

 Times Cited Count:4 Percentile:30.13(Instruments & Instrumentation)

no abstracts in English

Journal Articles

Study of metallofullerenes encapsulating actinides

Akiyama, Kazuhiko; Sueki, Keisuke*; Tsukada, Kazuaki; Yaita, Tsuyoshi; Miyake, Yoko*; Haba, Hiromitsu*; Asai, Masato; Kodama, Takeshi*; Kikuchi, Koichi*; Otsuki, Tsutomu*; et al.

Journal of Nuclear and Radiochemical Sciences, 3(1), p.151 - 154, 2002/06

The oxidation state of actinide elements encapsulated in fullerenes is studied. HPLC elution behavior of actinide-fullerenes is classified into two groups; the elution behavior of the first group, encapsulating U, Np, and Am, is similar to that of the light lanthanide-fullerenes, such as La, Ce, Pr, and Nd, while the behavior of the second group, encapsulating Th and Pa, is quite different from that of any lanthanide-fullerenes. The chemical species in the main HPLC elution peak of each group were identified as M@C82 and M@C84 (M = metal atom) from the mass of the U and Th fullerenes, respectively. The oxidation states of the U and Th atoms in the fullerenes were deduced to be 3+ and 4+, respectively, from the UV/vis/NIR absorption and XANES spectroscopy.

Journal Articles

X-ray absorption near-edge structure (XANES) spectral changes of 2-deoxy-D-ribose by irradiation within the energy region around the oxygen K-shell absorption edge

Akamatsu, Ken; Yokoya, Akinari

Journal of Synchrotron Radiation, 8(Part2), p.1001 - 1002, 2001/03

no abstracts in English

Journal Articles

Oxygen K-edge X-ray absorption near edge structures (XANES) of sublimated films of amino acids

Tanaka, Masahito*; Nakagawa, Kazumichi*; Koketsu, Toshiyuki*; Agui, Akane; Yokoya, Akinari

Journal of Synchrotron Radiation, 8(Part2), p.1009 - 1011, 2001/03

Amino acid molecules are known to be in the state of so-called "zwitter-ion" in solid phase and its extremely low vapour pressure makes ultra high vacuum experiment such as the XANES experiment possible. Recently, C-K edge XANES spectra of aromatic amino acids were studied experimentally and theoretically. Here we selected oxygen K-edge for XANES study of amino acids. From the view point of K-edge XANES study in amino acids, oxygen is interesting because its chemical states have the wealth of variety. A carboxylic group on the $$alpha$$ carbon is in the state of carboxylic anion -COO-, while carboxylic group in side-chain stays on -COOH, and some amino acids have -OH group in side-chain. Due to this variety of chemical environment, we can expect characteristic chemical shift for each oxygen atom in various amino acids. In this paper, we report a result of oxygen K-edge XANES spectra of amino acids (glycine, L-a-alanine, b-alanine, L-serine, L-asparic acid and L-tyrosine) films. We discuss the details of spectra on the basis of DV-X$$alpha$$ calculation.

Journal Articles

X-ray absorption near edge structures of DNA or its components around the oxygen K-shell edge

Akamatsu, Ken; Yokoya, Akinari

Radiation Research, 155(3), p.449 - 452, 2001/03

 Times Cited Count:19 Percentile:52.65(Biology)

no abstracts in English

Journal Articles

X-ray absorption studies of anodized monocrystalline 3C-SiC

Monguchi, Takuo*; Fujioka, Hiroshi*; Uragami, Takeshi*; Ono, Kanta*; Baba, Yuji; Oshima, Masaharu*

Journal of the Electrochemical Society, 147(2), p.741 - 743, 2000/02

 Times Cited Count:3 Percentile:14.88(Electrochemistry)

no abstracts in English

35 (Records 1-20 displayed on this page)