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Journal Articles

Benchmark study of DFT with Eu and Np M$"o$ssbauer 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

 Times Cited Count:0 Percentile:100

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 M$"o$ssbauer isomer shifts for $$^{151}$$Eu and $$^{237}$$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.

Journal Articles

On/off spin-crossover phenomenon and control of the transition temperature in assembled Iron(II) complexes

Nakashima, Satoru*; Kaneko, Masashi; Yoshinami, Keisuke*; Iwai, Saki*; Dote, Haruka*

Hyperfine Interactions, 239(1), p.39_1 - 39_15, 2018/12

 Times Cited Count:1 Percentile:29.61

The present study reveals the on/off of spin-crossover (SCO) phenomenon in assembled Fe(II) complexes bridged by bis(pyridyl) type ligand. Whether SCO phenomenon occurs or not in assembled Fe(II) complexes bridged by bis(pyridyl) type ligand is determined by local structure around iron atom. SCO phenomenon occurs when the coordinating pyridines facing to each other across the iron atom are propeller type, while the phenomenon does not occur when they are parallel type or distorted propeller type. DFT calculation explained that, in the shortening of Fe-pyridine bonds when changing from high-spin state to low-spin state, the pyridines of propeller type can approach the iron atom with smaller steric hindrance than those of parallel and distorted propeller type complexes. The local structure is controlled by introducing methyl substituent and introducing $$pi$$-system, changing SCO phenomenon. And the transition temperature of SCO is also controlled in assembled complexes bridged by 1,2-bis(4-pyridyl)ethane by mixing anionic ligand.

Journal Articles

Estimation of $$Delta$$${it R}$/${it R}$ values by benchmark study of the M$"o$ssbauer 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


 Times Cited Count:1 Percentile:27.03

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 $$^{99}$$Ru, $$^{189}$$Os M$"o$ssbauer isomer shifts. As the result, the computational values of the electron densities at nucleus position correlated with the experimental M$"o$ssbauer isomer shifts.

Journal Articles

New precise measurement of muonium hyperfine structure interval at J-PARC

Ueno, Yasuhiro*; Aoki, Masaharu*; Fukao, Yoshinori*; Higashi, Yoshitaka*; Higuchi, Takashi*; Iinuma, Hiromi*; Ikedo, Yutaka*; Ishida, Keiichi*; Ito, Takashi; Iwasaki, Masahiko*; et al.

Hyperfine Interactions, 238(1), p.14_1 - 14_6, 2017/11

 Times Cited Count:2 Percentile:12.39

Journal Articles

Local fields at nonmagnetic impurity sites in a perovskite $${rm La_{0.7}Ca_{0.3}MnO_3}$$

Sato, Wataru*; Komatsuda, Sayaka*; Osa, Akihiko; Sato, Tetsuya; Okubo, Yoshitaka*

Hyperfine Interactions, 237(1), p.113_1 - 113_6, 2016/12

 Times Cited Count:2 Percentile:26.64

The magnetic hyperfine field and electric field gradient at the$$^{111}$$Cd($$leftarrow$$ $$^{rm 111m}$$Cd) and $$^{rm 111}$$Cd($$leftarrow$$$$^{rm 111}$$In) probe nuclei introduced in a perovskite manganese oxide $${rm La_{0.7}Ca_{0.3}MnO_{3}}$$ ($$T_C$$ $$sim$$ 250 K) were measured for the study of the local magnetism and structure by means of time-differential perturbed angular correlation spectroscopy. In the ferromagnetic phase at 77 K, a very slight supertransferred magnetic hyperfine field (SMHF) ($$<$$ 0.014 T) combined with a well-defined electric field gradient was observed at the nonmagnetic $$^{111}$$Cd nucleus on the La/Ca A site. This observation suggests that the large magnetic hyperfine field ($$B_{hf}$$ = 6.9 T) measured, in our previous work, at the $$^{140}$$Ce probe nucleus on the A site originates from the contribution of a 4$$f$$ spin oriented by the SMHF from adjacent Mn ions.

Journal Articles

New muonium HFS measurements at J-PARC/MUSE

Strasser, P.*; Aoki, Masaharu*; Fukao, Yoshinori*; Higashi, Yoshitaka*; Higuchi, Takashi*; Iinuma, Hiromi*; Ikedo, Yutaka*; Ishida, Keiichi*; Ito, Takashi; Iwasaki, Masahiko*; et al.

Hyperfine Interactions, 237(1), p.124_1 - 124_9, 2016/12

 Times Cited Count:5 Percentile:6.11

Journal Articles

Development of $$^{125}$$Te synchrotron-radiation-based M$"o$ssbauer spectroscopy

Kurokuzu, Masayuki*; Kitao, Shinji*; Kobayashi, Yasuhiro*; Saito, Makina*; Masuda, Ryo*; Mitsui, Takaya; Yoda, Yoshitaka*; Seto, Makoto*

Hyperfine Interactions, 226(1), p.687 - 691, 2014/04

 Times Cited Count:2 Percentile:34.48

Journal Articles

Defect-fluorite oxides; Ln (Eu and Gd) M$"o$ssbauer study coupled with new defect-crystal-chemistry model

Nakamura, Akio; Igawa, Naoki; Okamoto, Yoshihiro; Wang, J.*; Hinatsu, Yukio*; Takahashi, Masashi*; Takeda, Masuo*

Hyperfine Interactions, 217(1-3), p.17 - 26, 2013/04

 Times Cited Count:1 Percentile:43.96

Journal Articles

Laser ablation absorption spectroscopy for remote analysis of uranium

Miyabe, Masabumi; Oba, Masaki; Iimura, Hideki; Akaoka, Katsuaki; Maruyama, Yoichiro; Oba, Hironori; Tampo, Motonobu; Wakaida, Ikuo

Hyperfine Interactions, 216(1-3), p.71 - 77, 2013/04

 Times Cited Count:5 Percentile:16.16

To determine experimental conditions suitable for isotope analysis, we studied the plume dynamics of uranium. A uranium oxide sample was ablated by 2nd harmonic radiation from a Nd:YAG laser at a fluence of 0.5 J/cm$$^{2}$$. The temporal evolution of the ablation plume was investigated in 800 Pa helium environment. It was found that the observation at 3-5$$times$$10$$^{-6}$$s after the ablation at the height of about 2.5 mm are most suited for obtaining higher sensitivity. Using the established conditions, we obtained the limit of detection of the isotope ratio ($$^{235}$$U/$$^{238}$$U) to be 0.01%. In addition, the limit of detection of elemental abundance of uranium in uranium glass was also evaluated.

Journal Articles

Synchrotron radiation $$^{57}$$Fe-M$"o$ssbauer spectroscopy using nuclear monochromator

Mitsui, Takaya; Masuda, Ryo; Hirao, Naohisa*; Mibu, Ko*; Seto, Makoto

Hyperfine Interactions, 204(1-3), p.97 - 100, 2012/04

 Times Cited Count:1 Percentile:33.91

Journal Articles

$$^{155}$$Gd M$"o$ssbauer spectroscopic and powder X-ray diffraction study of CeO$$_{2}$$ - GdO$$_{1.5}$$ solid solution

Nakamura, Akio; imai, kazutaka*; Igawa, Naoki; Okamoto, Yoshihiro; Yamamoto, Etsuji; Matsukawa, Shiro*; Takahashi, Masashi*

Hyperfine Interactions, 207(1-3), p.67 - 71, 2012/03

 Times Cited Count:3 Percentile:13.89

Journal Articles

An in situ M$"{o}$ssbauer study using synchrotron radiation

Masuda, Ryo; Mitsui, Takaya; Ito, Keiji*; Sakaki, Koji*; Enoki, Hirotoshi*; Nakamura, Yumiko*; Seto, Makoto

Hyperfine Interactions, 204(1-3), p.139 - 142, 2012/03

 Times Cited Count:2 Percentile:19.64

We have been developing a system for in situ M$"{o}$ssbauer studies using synchrotron radiation (SR) to elucidate the mechanism of hydrogenation processes. In the system, samples reacts in an atmosphere chamber and SR-based M$"{o}$ssbauer spectra using variable-frequency nuclear monochromator and energy spectra of inelastic nuclear resonant scattering (NRS) of SR are measured. As a feasibility study, the temperature dependence of the M$"{o}$ssbauer and inelastic NRS spectra of $$^{57}$$Fe in $$c$$-GdFe$$_2$$H$$_3$$ under vacuum were measured. In both spectra, clear differences were observed between 373 K and 573 K. These differences can be interpreted by the change of microscopic environment around Fe at the dehydrogenation. Thus, it is confirmed that this system works well enough to perform the in-situ M$"{o}$ssbauer study on the dehydrogenation of $$c$$-GdFe$$_2$$H$$_3$$.

Journal Articles

M$"o$ssbauer spectroscopic evidence on the heme binding to the proximal histidine in unfolded carbonmonoxy myoglobin by guanidine hydrochloride

Harami, Taikan*; Kitao, Shinji*; Kobayashi, Yasuhiro*; Mitsui, Takaya

Hyperfine Interactions, 181(1-3), p.179 - 187, 2008/01

 Times Cited Count:2 Percentile:75.74(Physics, Atomic, Molecular & Chemical)

The unfolded heme structure in myoglobin is controversial because of no chance of direct X-ray structure analyses. The unfolding of carbonmonoxy myoglobin (MbCO) by guanidine hydrochloride (GdnHCl) was studied by the M$"o$ssbauer spectroscopy. The spectra show the presence of a sort of spectrum in the unfolded MbCO, independent on the concentration of GdnHCl from 1 to 6 M and the increase of the fraction of unfolded MbCO, depending on the GdnHCl concentration. The isomer shift of the iron of heme in the unfolded MbCO was identified to be different from that of the native MbCO as the globin structure in Mb collapses under the unfolded conditions. This result and the existing related M$"o$ssbauer data proved that the heme in the unfolded MbCO may remain coordinated to the proximal histidine.

Journal Articles

$$^{238}$$U M$"o$ssbauer study on the 5f-quadrupoles in uranium-based intermetallics

Tsutsui, Satoshi*; Nakada, Masami; Nasu, Saburo*; Homma, Tetsuo*; Tokiwa, Yoshifumi; Aoki, Dai*; Wisniewski, P.*; Haga, Yoshinori; Onuki, Yoshichika

Hyperfine Interactions, 141/142(1-4), p.237 - 242, 2002/06

 Times Cited Count:1 Percentile:90.75(Physics, Atomic, Molecular & Chemical)

We have determined the distribution of the 5f-quadrupoles and detected the 5f-quadrupole order in the uranium intermetallics, uranium dipnictides and UPd$$_3$$, with $$^{238}$$ Mo"ssbauer spectroscopy. We have declared that the distribution of the 5f-quadrupoles depends on the magnetic sequence in uranium dipnictides. The distribution of the 5f-quadrupole is spherical in UBi$$_2$$, while those are oblate within c-plane in UP$$_2$$, UAs$$_2$$ and USb$$_2$$. We have observed the sudden drop of the recoil-free fraction above the transition temperature of the quadrupole order in UPd$$_3$$. The present result suggests the change of the phonon states due to the quadrupole order in this compound.

Journal Articles

$$^{238}$$U and $$^{57}$$Fe M$"o$ssbauer spectroscopic study of UFe$$_{2}$$

Tsutsui, Satoshi; Nakada, Masami; Kobayashi, Yasuhiro*; Nasu, Saburo*; Haga, Yoshinori; Onuki, Yoshichika

Hyperfine Interactions, 133(1-4), p.17 - 21, 2001/11

no abstracts in English

Journal Articles

$$^{238}$$U M$"o$ssbauer study on the magnetic properties of uranium-based heavy fermion superconductors

Tsutsui, Satoshi; Nakada, Masami; Nasu, Saburo*; Haga, Yoshinori; Homma, Tetsuo; Yamamoto, Etsuji; Okuni, Hitoshi*; Onuki, Yoshichika

Hyperfine Interactions, 126(1-4), p.335 - 340, 2000/07

 Times Cited Count:6 Percentile:60.12(Physics, Atomic, Molecular & Chemical)

no abstracts in English

Journal Articles

He accumulation effect in solid and liquid D-T mixture

*; Nagamine, Kanetada*; Matsuzaki, Teiichiro*; Ishida, Katsuhiko*; *; Sakamoto, Shinichi*; *; Tanase, Masakazu; Kato, Mineo; Kurosawa, Kiyoyuki; et al.

Hyperfine Interactions, 118(1-4), p.213 - 215, 1999/00

no abstracts in English

Journal Articles

Muon catalyzed fusion and muon to $$^{3}$$He transfer in solid T$$_{2}$$ studied by X-ray and neutron detection

Matsuzaki, Teiichiro*; Nagamine, Kanetada*; Ishida, Katsuhiko*; *; *; Tanase, Masakazu; Kato, Mineo; Kurosawa, Kiyoyuki; Hashimoto, Masashi; Sugai, Hiroyuki; et al.

Hyperfine Interactions, 118(1-4), p.229 - 234, 1999/00

no abstracts in English

Journal Articles

Tritium gas handling system for muon catalyzed fusion research at RIKEN-RAL muon facility

Matsuzaki, Teiichiro*; Nagamine, Kanetada*; Tanase, Masakazu; Kato, Mineo; Kurosawa, Kiyoyuki; Ishida, Katsuhiko*; *; *; G.H.Eaton*

Hyperfine Interactions, 119(1-4), p.361 - 363, 1999/00

no abstracts in English

Journal Articles

Measurement of X-rays from muon to $$alpha$$ sticking and fusion neutrons in solid/liquid D-T mixtures of high tritium concentration

Ishida, Katsuhiko*; Nagamine, Kanetada*; Matsuzaki, Teiichiro*; *; *; Sakamoto, Shinichi*; *; Tanase, Masakazu; Kato, Mineo; Kurosawa, Kiyoyuki; et al.

Hyperfine Interactions, 118(1-4), p.203 - 208, 1999/00

no abstracts in English

32 (Records 1-20 displayed on this page)