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Journal Articles

Momentum-resolved resonant inelastic X-ray scattering on a single crystal under high pressure

Yoshida, Masahiro*; Ishii, Kenji; Jarrige, I.*; Watanuki, Tetsu; Kudo, Kazutaka*; Koike, Yoji*; Kumagai, Kenichi*; Hiraoka, Nozomu*; Ishii, Hirofumi*; Tsuei, K.-D.*; et al.

Journal of Synchrotron Radiation, 21(1), p.131 - 135, 2014/01

 Times Cited Count:3 Percentile:19.11(Instruments & Instrumentation)

Journal Articles

Negative and positive ion trapping by isotopic molecules in cryocrystals in case of solid parahydrogen containing electrons and H$$_{6}$$$$^{+}$$ radical cations

Shimizu, Yuta*; Inagaki, Makoto*; Kumada, Takayuki; Kumagai, Jun*

Journal of Chemical Physics, 132(24), p.244503_1 - 244503_8, 2010/06

 Times Cited Count:0 Percentile:0.01(Chemistry, Physical)

We performed electron spin resonance studies of trapped electrons and H$$_{6}$$$$^{+}$$ radical cations produced by radiolysis of solid para-H$$_{2}$$, para-H$$_{2}$$-ortho-D$$_{2}$$, and para-H$$_{2}$$-HD mixtures. Yields of both trapped electrons, and H$$_{6}$$$$^{+}$$ radical cations, and its isotopic analogues increased with increasing the concentration of ortho-D$$_{2}$$ and HD concentrations in solid para-H$$_{2}$$. We have concluded that electrons were found trapped nearby an ortho-D$$_{2}$$ or an HD in solid para-H$$_{2}$$ due to a the long-range charge-induced dipole and charge-induced quadrupole interactions between an electrons and an isotopic hydrogen molecules.

Journal Articles

H atom, e$$^{-}$$, and H$$_6^{+}$$ ions produced in irradiated solid hydrogens; An Electron spin resonance study

Kumada, Takayuki; Ushida, Takahiro*; Shimizu, Yuta*; Kumagai, Jun*

Radiation Physics and Chemistry, 77(10-12), p.1318 - 1322, 2008/10

 Times Cited Count:8 Percentile:49.21(Chemistry, Physical)

Very recently, we succeeded in observing totally more than 50 sharp ESR lines of H$$_6^{+}$$ and its isotope substituents H$$_{5}$$D$$^{+}$$, H$$_{4}$$D$$_2^{+}$$, and H$$_{2}$$D$$_4^{+}$$ in $$gamma$$-ray irradiated solid para-H$$_{2}$$ (p-H$$_{2}$$) and p-H$$_{2}$$-D$$_{2}$$ and p-H$$_{2}$$-HD mixtures. We also observed isotope-substitution reactions such as H$$_6^{+}$$ + HD $$rightarrow$$ H$$_{5}$$D$$^{+}$$ + H$$_{2}$$ and H$$_6^{+}$$ + D$$_{2}$$ $$rightarrow$$ H$$_{4}$$D$$_2^{+}$$ + H$$_{2}$$. The H$$_6^{+}$$ ions diffuse in solid p-H$$_{2}$$ via the repetition of H$$_6^{+}$$ + H$$_{2}$$ $$rightarrow$$ H$$_{2}$$ + H$$_6^{+}$$ reactions which terminate by the H$$_{6}$$$$^{+}$$ + HD or H$$_6^{+}$$ + D$$_{2}$$ reactions. The H$$_{5}$$D$$^{+}$$, H$$_{4}$$D$$_2^{+}$$, and H$$_{2}$$D$$_4^{+}$$ ions, on the other hand, are immobile in solid p-H$$_{2}$$. They decay via geminate recombination with trapped electrons within the time-scale of 5 hours.

Journal Articles

Isotope effects on the spin-density distribution in the H$$_6^{+}$$ clusters; Direct ${it ab initio}$ molecular dynamics study

Kurosaki, Yuzuru; Shimizu, Yuta*; Kumagai, Jun*

Chemical Physics Letters, 455(1-3), p.59 - 63, 2008/03

 Times Cited Count:2 Percentile:5.23(Chemistry, Physical)

Direct ab initio molecular dynamics calculations have been carried out for the H$$_6^{+}$$ cluster and its isotopic analogues: [H$$_{2}$$(H$$_{2}$$)H$$_{2}$$]$$^{+}$$, [H$$_{2}$$(H$$_{2}$$)D$$_{2}$$]$$^{+}$$, and [H$$_{2}$$(HD)H$$_{2}$$]$$^{+}$$. The calculations predict that the average geometry over the trajectories becomes asymmetric in both the deuterated clusters [H$$_{2}$$(H$$_{2}$$)D$$_{2}$$]$$^{+}$$ and [H$$_{2}$$(HD)H$$_{2}$$]$$^{+}$$, causing disproportion in the spin density that determines hyperfine coupling constants (HFCCs). This prediction agrees well with a recent ESR study that observed the isotope effects on the HFCCs for the central H$$_{2}$$ in these clusters generated in $$gamma$$-irradiated solid $$p$$-H$$_{2}$$. Thus the present result strongly supports the H$$_6^{+}$$ cluster formation in the solid $$p$$-H$$_{2}$$.

Journal Articles

Electron spin resonance study on H$$_6$$$$^+$$, H$$_5$$D$$^+$$, H$$_4$$D$$_2$$$$^+$$, and H$$_2$$D$$_4$$$$^+$$ in solid parahydrogen

Kumagai, Jun*; Inagaki, Hiroki*; Kariya, Susumu*; Ushida, Takahiro*; Shimizu, Yuta*; Kumada, Takayuki

Journal of Chemical Physics, 127(2), p.024505_1 - 024505_13, 2007/07

We carried out an electron spin resonance (ESR) study on hydrogen ion radicals produced by radiolysis of solid parahydrogen. We newly observed totally more than fifty resolved lines in irradiated solid parahydrogens. We assigned these lines to be isotope substituents of H$$_2$$$$^+$$-core H$$_6$$$$^+$$ ions such as H$$_5$$D$$^+$$, H$$_4$$D$$_2$$$$^+$$, and H$$_2$$D$$_4$$$$^+$$ throughout comparison of their ESR parameters with theoretical results. These results show conclusive evidence that H$$_2$$$$^+$$-core H$$_6$$$$^+$$ ions are produced and stably trapped in irradiated solid hydrogens. We also observed a lowering symmetry on electron wave function in H$$_5$$D$$^+$$ and H$$_4$$D$$_2$$$$^+$$, and isotope-substitution reactions such as H$$_6$$$$^+$$+D$$_2$$$$rightarrow $$H$$_4$$D$$_2$$$$^+$$+H$$_2$$ and H$$_6$$$$^+$$+HD$$rightarrow $$H$$_5$$D$$^+$$+H$$_2$$.

Journal Articles

Electron spin resonance study on H$$_{6}$$$$^{+}$$, H$$_{5}$$D$$^{+}$$, H$$_{4}$$D$$_{2}$$$$^{+}$$, and H$$_{2}$$D$$_{4}$$$$^{+}$$ in solid parahydrogen

Kumagai, Jun*; Inagaki, Hiroshi*; Kariya, Susumu*; Ushida, Takahiro*; Shimizu, Yuta*; Kumada, Takayuki

Journal of Chemical Physics, 127(2), p.024505_1 - 024505_13, 2007/07

 Times Cited Count:17 Percentile:51.97(Chemistry, Physical)

We carried out an electron spin resonance (ESR) study on hydrogen ion radicals produced by radiolysis of solid parahydrogen. In addition to quartet ESR lines proposed to be H$$_{2}$$$$^{+}$$-core H$$_{6}$$$$^{+}$$ ions in solid parahydrogen, we newly observed totally more than fifty resolved lines in $$gamma$$-ray irradiated solid para-H$$_{2}$$-ortho-D$$_{2}$$ (1 mol %) and para-H$$_{2}$$-HD (1 mol %) mixtures. We assigned these lines to be isotope substituents of H$$_{2}$$$$^{+}$$-core H$$_{6}$$$$^{+}$$ ions such as H$$_{5}$$D$$^{+}$$, H$$_{4}$$D$$_{2}$$$$^{+}$$, and H$$_{2}$$D$$_{4}$$$$^{+}$$ throughout comparison of their ESR parameters with theoretical results.

Journal Articles

Momentum-dependent charge excitations of a two-leg ladder; Resonant inelastic X-ray scattering of (La,Sr,Ca)$$_{14}$$Cu$$_{24}$$O$$_{41}$$

Ishii, Kenji; Tsutsui, Kenji*; Toyama, Takami*; Inami, Toshiya; Mizuki, Junichiro; Murakami, Yoichi*; Endo, Yasuo*; Maekawa, Sadamichi*; Kudo, Kazutaka*; Koike, Yoji*; et al.

Physical Review B, 76(4), p.045124_1 - 045124_7, 2007/07

 Times Cited Count:20 Percentile:63.5(Materials Science, Multidisciplinary)

(La,Sr,Ca)$$_{14}$$Cu$$_{24}$$O$$_{41}$$ is an attractive material in connection with high-$$T_{rm c}$$ superconductivity because Sr$$_{0.4}$$Ca$$_{13.6}$$Cu$$_{24}$$O$$_{41}$$ becomes a superconductor under high pressure without the CuO$$_2$$ planes. We present RIXS at the Cu $$K$$-edge of (La,Sr,Ca)$$_{14}$$Cu$$_{24}$$O$$_{41}$$ focusing on the momentum dependence of interband excitation across the Mott gap and the intraband excitation below the gap as a function of hole concentration. The experimental results are consistent with the theoretical predictions.

Journal Articles

Application of ionizing radiation in our life

Kojima, Takuji; Hirade, Tetsuya; Kumagai, Jun*

Hoshasen Kagaku No Susume; Denshi, Ion, Hikari No Bimu Ga Kurashi O Kaeru, Sangyo O Tsukuru, p.1 - 23, 2006/02

no abstracts in English

Journal Articles

Application of ionizing radiation and radiation chemistry, 2

Kojima, Takuji; Hirade, Tetsuya; Kumagai, Jun*

Hoshasen Kagaku No Susume; Denshi, Ion, Hikari No Bimu Ga Kurashi O Kaeru, Sangyo O Tsukuru, p.25 - 38, 2006/02

no abstracts in English

Journal Articles

Absence of recombination of neighboring H atoms in highly purified solid parahydrogen; Electron spin resonance, electron-nuclear double resonance, and electron spin echo studies

Kumada, Takayuki; Sakakibara, Masahiro*; Nagasaka, Toshimitsu*; Fukuta, Hiroya*; Kumagai, Jun*; Miyazaki, Tetsuo*

Journal of Chemical Physics, 116(3), p.1109 - 1119, 2002/01

 Times Cited Count:43 Percentile:78.02(Chemistry, Physical)

We have studied diffusion and recombination of H atoms in solid hydrogen using ESR, ENDOR, and ESE spectrometer. The rate constant for recombination of H atoms in highly purified parahydrogen was found to be much smaller than that expected by diffusion coefficient. This result indicates that the H atoms do not recombine in the absence of energy dispersion path in highly purified parahydrogen.

Journal Articles

High-resolution electron spin resonance spectroscopy of ethyl radicals in solid parahydrogen

Kumada, Takayuki; Kumagai, Jun*; Miyazaki, Tetsuo*

Journal of Chemical Physics, 114(22), p.10024 - 10030, 2001/06

 Times Cited Count:14 Percentile:41.33(Chemistry, Physical)

no abstracts in English

Journal Articles

Trapping sites of hydrogen atoms in solid HD and D$$_{2}$$; An Electron spin echo study

Kumada, Takayuki; Noda, Tomoyoshi*; Kumagai, Jun*; Aratono, Yasuyuki; Miyazaki, Tetsuro

Journal of Chemical Physics, 111(24), p.10974 - 10978, 1999/12

 Times Cited Count:10 Percentile:31.13(Chemistry, Physical)

no abstracts in English

Journal Articles

Decay of H$$_{2-}$$ anions in solid parahydrogen via two-stage quantum tunneling diffusion process

Kumada, Takayuki; *; *; Kumagai, Jun*; Aratono, Yasuyuki; Miyazaki, Tetsuro*

Journal of Low Temperature Physics, 114(5-6), p.413 - 429, 1999/00

no abstracts in English

Journal Articles

Observation of electron bubbles in para-H$$_{2}$$-D$$_{2}$$(HD) mixtures by high-resolution ESR spectroscopy

Kumada, Takayuki; *; Kumagai, Jun*; Aratono, Yasuyuki; Miyazaki, Tetsuro*

Journal of Physical Chemistry A, 103(45), p.8966 - 8968, 1999/00

 Times Cited Count:13 Percentile:39.04(Chemistry, Physical)

no abstracts in English

Journal Articles

An ENDOR spectrum of H atoms in solid H$$_{2}$$

Kumada, Takayuki; *; Noda, Tomoyoshi*; Kumagai, Jun*; Aratono, Yasuyuki; Miyazaki, Tetsuro*

Chemical Physics Letters, 288(5-6), p.755 - 759, 1998/00

 Times Cited Count:27 Percentile:64.6(Chemistry, Physical)

no abstracts in English

JAEA Reports

Design study on H.L.W. geologic repository, IV; for 1984

Ara, Hiroshige*; Fukumitsu, Kenji*; Iizuka, Yunosuke*; Ishii, Takashi*; Izumiya, Yasushi*; Imazu, Masanori*; Utsugida, Yoshizo*; Hasegawa, Makoto*; Maeda, Masaya*; Yabe, Yukio*; et al.

PNC TJ199 84-04VOL1, 20 Pages, 1984/03

PNC-TJ199-84-04VOL1.pdf:0.88MB

None

Oral presentation

Charge excitations in (La,Sr,Ca)$$_{14}$$Cu$$_{24}$$O$$_{41}$$ studied by resonant inelastic X-ray scattering

Ishii, Kenji; Tsutsui, Kenji*; Toyama, Takami*; Mizuki, Junichiro; Endo, Yasuo; Maekawa, Sadamichi*; Kudo, Kazutaka*; Koike, Yoji*; Kumagai, Kenichi*

no journal, , 

(La,Sr,Ca)$$_{14}$$Cu$$_{24}$$O$$_{41}$$ is an attractive material in connection with high-$$T_{rm c}$$ superconductivity because Sr$$_{0.4}$$Ca$$_{13.6}$$Cu$$_{24}$$O$$_{41}$$ becomes a superconductor under high pressure without the CuO$$_2$$ planes. We present RIXS at the Cu $$K$$-edge of (La,Sr,Ca)$$_{14}$$Cu$$_{24}$$O$$_{41}$$ focusing on the momentum dependence of interband excitation across the Mott gap and the intraband excitation below the gap as a function of hole concentration. The experimental results are consistent with the theoretical predictions.

Oral presentation

Resonant inelastic X-ray scattering study of (La,Sr,Ca)$$_{14}$$Cu$$_{24}$$O$$_{41}$$

Ishii, Kenji; Tsutsui, Kenji*; Toyama, Takami*; Inami, Toshiya; Mizuki, Junichiro; Murakami, Yoichi*; Endo, Yasuo*; Maekawa, Sadamichi*; Kudo, Kazutaka*; Koike, Yoji*; et al.

no journal, , 

(La,Sr,Ca)$$_{14}$$Cu$$_{24}$$O$$_{41}$$ is an attractive material in connection with high-$$T_{rm c}$$ superconductivity because Sr$$_{0.4}$$Ca$$_{13.6}$$Cu$$_{24}$$O$$_{41}$$ becomes a superconductor under high pressure without the CuO$$_2$$ planes. We present RIXS at the Cu $$K$$-edge of (La,Sr,Ca)$$_{14}$$Cu$$_{24}$$O$$_{41}$$ focusing on the momentum dependence of interband excitation across the Mott gap and the intraband excitation below the gap as a function of hole concentration. The experimental results are consistent with the theoretical predictions.

Oral presentation

Resonant inelastic X-ray scattering of (La,Sr,Ca)$$_{14}$$Cu$$_{24}$$O$$_{41}$$

Ishii, Kenji; Tsutsui, Kenji*; Toyama, Takami*; Inami, Toshiya; Mizuki, Junichiro; Murakami, Yoichi*; Endo, Yasuo*; Maekawa, Sadamichi*; Kudo, Kazutaka*; Koike, Yoji*; et al.

no journal, , 

(La,Sr,Ca)$$_{14}$$Cu$$_{24}$$O$$_{41}$$ is an attractive material in connection with high-$$T_{rm c}$$ superconductivity because Sr$$_{0.4}$$Ca$$_{13.6}$$Cu$$_{24}$$O$$_{41}$$ becomes a superconductor under high pressure without the CuO$$_2$$ planes. We present RIXS at the Cu $$K$$-edge of (La,Sr,Ca)$$_{14}$$Cu$$_{24}$$O$$_{41}$$ focusing on the momentum dependence of interband excitation across the Mott gap and the intraband excitation below the gap as a function of hole concentration. The experimental results are consistent with the theoretical predictions.

Oral presentation

Resonant inelastic X-ray scattering of (La,Sr,Ca)$$_{14}$$Cu$$_{24}$$O$$_{41}$$

Ishii, Kenji; Tsutsui, Kenji*; Toyama, Takami*; Inami, Toshiya; Mizuki, Junichiro; Murakami, Yoichi*; Endo, Yasuo*; Maekawa, Sadamichi*; Kudo, Kazutaka*; Koike, Yoji*; et al.

no journal, , 

(La,Sr,Ca)$$_{14}$$Cu$$_{24}$$O$$_{41}$$ is an attractive material in connection with high-$$T_{rm c}$$ superconductivity because Sr$$_{0.4}$$Ca$$_{13.6}$$Cu$$_{24}$$O$$_{41}$$ becomes a superconductor under high pressure without the CuO$$_2$$ planes. We present RIXS at the Cu $$K$$-edge of (La,Sr,Ca)$$_{14}$$Cu$$_{24}$$O$$_{41}$$ focusing on the momentum dependence of interband excitation across the Mott gap and the intraband excitation below the gap as a function of hole concentration. The experimental results are consistent with the theoretical predictions.

31 (Records 1-20 displayed on this page)