HARADA, Yoshihisa

 

[Graduation and Degree]

 Mar. 1995   Department of Applied Physics, Faculty of Engineering, The University of Tokyo

 Mar. 2000   Graduate School of Engineering, Doctor Course (Applied Physics major), The University of Tokyo

 Mar. 2000   Doctor of Engineering, The University of Tokyo

          (Thesis title: Polarized soft X-ray Raman scattering study on light transition metal compounds and sodium compounds)

 

[Professional Career]

 Apr.1999-Mar.2000    Fellow of Japan Society for the Promotion of Science (JSPS)

Apr.2000-Mar.2003    Special postdoctoral researcher, Riken Harima Institute

 Apr.2003-May.2007     Contract researcher, Riken Harima Institute

 Jun.2007-Apr.2009     Contract lecturer, Applied Chemistry, The University of Tokyo

 May.2009-Nov.2011  Contract Associate Professor, Applied Chemistry, The University of Tokyo

 Dec.2011-present         Associate Professor, ISSP, University of Tokyo

 

[Awards]

1.      Japanese Society for Synchrotron Radiation Research, Young Scientist Award, 2005

2.      The Physical Society of Japan, Best Paper Award, 2004

 

[Recent Research Achievements]

1. Construction of ultrahigh resolution soft X-ray emission spectrometer for solid state physics and various applications

Resonant soft X-ray emission spectroscopy (RIXS) provides element-, orbital (or symmetry)-, spin state-, or momentum selective electronic structure of a material. The world-record energy resolution at present can be improved principally by a factor of two considering the lifetime of the RIXS final state. RIXS also has promising versatility since it is insensitive to charging problems in insulators, thus applicable even to liquids and wet materials. However, the small acceptance angle of the emission spectrometer and low cross-section of the X-ray emission process hampered rapid growth of this spectroscopy. After improving the mechanics of the soft X-ray emission spectrometer for more than 15 years, we have finally constructed an ultrahigh energy resolution (E/DE > 5000) soft X-ray emission spectrometer which balances energy resolution and detection efficiency. In order to expand its use in materials science, we have developed an in situ liquid cell, a battery cell for operando spectroscopy, a magnetic-field applying device, a humidity controlled cell along with precise temperature control.

2. Operando electronic structure analyses of energy materials

Using the above battery cell system we applied RIXS for energy materials, i.e. carbon-based oxygen reduction catalyst as a fuel cell cathode catalyst and LiMn2O4 as a typical lithium ion battery electrode. For the fuel cell catalyst, we found that the initial inert metallic Fe changes into divalent Fe during fuel cell operation, which in turn will contribute to the oxygen reduction reaction. We also found the role of edge exposure and graphitic nitrogen in the carbon network on the oxygen reduction reaction. Considering the role of each element, a highly active and durable carbon-based catalyst has been synthesized applying a multi-step pyrolysis method. For the soft X-ray absorption/emission analyses of LiMn2O4 electrode in the lithium ion battery, we found that charge/discharge occur mostly on the ligand site through strong hybridization between Mn 3d and ligand 2p orbitals, which will concertedly induce local structural change around Mn site upon Li desorption/insertion and cause the deterioration of the electrode. These battery studies using synchrotron X-rays provide unique information and thus developed into collaborations with Toyota Motor Corporation and Asahi-Kasei Chemicals.

 

3. Electronic structure analyses of water and solutions

Using the above liquid cell system we applied RIXS for water and solutions. From high resolution soft X-ray emission spectra we found two distinctive lone pair peaks which correspond to mainly two fluctuating local hydrogen bond configurations in liquid (drinking) water. We confirmed this interpretation by isotope effect, temperature dependence and polarization dependence of pure liquid water, and analyzing a model system having lesser number of hydrogen bond like acetonitrile or 3-methyl-pyridine solutions. Moreover, we extracted the actual size of the local domains (which will be a fraction of the two components with tetrahedrally coordinated water) to be around 1nm using small angle X-ray scattering experiments. A series of these X-ray spectroscopic studies have raised considerable attention and discussion about the local structure of water from the view point of electronic structure, which is now extended to a wide range of theoretical and experimental studies on aqueous solutions using synchrotron soft X-rays.

 

4. Electronic structure analyses of the reaction center in metalloproteins

When applied to metalloproteins, soft X-ray RIXS can be a unique solution to extract transition metal 3d states in the active metalloproteins. We applied this technique to the most fundamental metalloprotein, myoglobin (Mb), like a hydrogen among elements. By circulating the active Mb solution we have successfully obtained the Fe 3d states of the heme center in Mb. Although their nominal spin state and valence number should change depending on the type of adsorbed molecules such as O2, CN, H2O NH3 etc., we found that their electronic structure is quite similar among them, suggesting the role of anisotropically hybridized ligand states that tune the charge and spin state to reduce the energy barrier against molecular adsorption. This is a real photon-hungry experiment, and thus expected to break a new scientific field using next generation synchrotron light sources and X-ray free electron lasers.

 

5. Development of element and chemical-state selective soft X-ray vibrational spectroscopy

Using the ultrahigh resolution RIXS, an anisotropic vibrational mode around 100 meV was observed in anatase TiO2, which is the direct consequence of the anisotropic polaronic screening mechanism in the dielectric environment of anatase TiO2.

When applying the same method to liquid water, we observed multiple OH stretching vibrational excitation profiles reflecting the local hydrogen bond configuration. The energy of the first vibrational excitation for the pre-edge excitation well coincides with that for the gas phase water, strongly suggesting the hydrogen-bond broken picture of the pre-edge peak in the O 1s X-ray absorption, while at post edge excitation the energy is going down from 0.453 eV to 0.426 eV, which again well coincides with that for the ice-like water. This method is very original and promising because we can directly compare the local structural information from the vibrational profile to the local electronic structure information from the valence band profile in the same spectrum. This can easily be extended to the applications like the study on the hydration of solutes and ions in the solution.

[Publication List]

118. Enhancement of the hydrogen-bonding network of water confined in a polyelectrolyte brush

K. Yamazoe, Y. Higaki, Y. Inutsuka, J. Miyawaki, Y. Cui, A. Takahara, and Y. Harada

Langmuir, accepted.

 

117. A Compact Permanent Magnet System for Measuring Magnetic Circular Dichroism in Resonant Inelastic Soft X-ray Scattering

J. Miyawaki, S. Suga, H. Fujiwara, H. Niwa, H. Kiuchi and Y. Harada

J. Sync. Rad., 24 (2017) 449-455.

 

116. Interface electronic structure at the topological insulator - ferrimagnetic insulator junction

Y. Kubota, K. Murata, J. Miyawaki, K. Ozawa, M. Onbasli, T. Shirasawa, B. Feng, Sh. Yamamoto, R.-Y. Liu, S. Yamamoto, S.K. Mahatha, P. Sheverdyaeva, P. Moras, C.A. Ross, S. Suga, Y. Harada, K.L. Wang, and I. Matsuda

J. Phys. Cond. Matt., 29, (2017) 055002 (1-6).

 

115. Hybridization and electron-phonon coupling in ferroelectric BaTiO3 probed by Resonant Inelastic X-ray Scattering

S. Fatale, S. Moser, J. Miyawaki, Y. Harada, and M. Grioni

Phys. Rev. B, 94 (2016) 195131 (1-6).

 

114. Combined Experimental and Computational Analyses on the Electronic Structure of Alluaudite-type Sodium Iron Sulfate

G. Oyama, H. Kiuchi, S. Cheong Chung, Y. Harada, A. Yamada

J. Phys. Chem. C, 120 (2016) 23323-23328.

 

113. Resonant inelastic x-ray scattering study of entangled spin-orbital excitations in superconducting PrFeAsO0.7

T. Nomura, Y. Harada, H. Niwa, K. Ishii, M. Ishikado, S. Shamoto, and I. Jarrige

Phys. Rev. B, 94 (2016) 035134 (1-9).

 

112. X-ray and Electron Spectroscopy of Water

T. Fransson, Y. Harada, N. Kosugi, N.A. Besley, B. Winter, J. Rehr, L.G.M. Pettersson and A. Nilsson

Chem. Rev., 116 (2016) 7551–7569.

 

111. In situ hard X-ray photoelectron study of O2 and H2O adsorption on Pt nanoparticles

Y. Cui, Y. Harada, E. Ikenaga, R. Li, N. Nakamura, T. Hatanaka, M. Ando, T. Yoshida, G-L. Li, and M. Oshima

J. Phys. Chem. C, 120 (2016) 10936-10940.

 

110. Intermediate Honeycomb Ordering to Trigger Oxygen Redox Chemistry in Layered Battery Electrode

B. M. de Boisse, G. Liu, J. Ma, S.-i. Nishimura, S.-C. Chung, H. Kiuchi, Y. Harada, J. Kikkawa, Y. Kobayashi, M. Okubo, and A. Yamada

Nat. Commun., 7 (2016) 11397 (1-9).

 

109. Pt-free carbon-based fuel cell catalyst prepared from spherical polyimide for enhanced oxygen diffusion

Y. Nabae, S. Nagata, T. Hayakawa, H. Niwa, Y. Harada, M. Oshima, A. Isoda, A. Matsunaga, and K. Tanaka

Sci. Rep. 6 (2016) 23276 (1-7).

 

108. Lewis basicity of nitrogen-doped graphite observed by CO2 chemisorption

H. Kiuchi, R. Shibuya, T. Kondo, J. Nakamura, H. Niwa, J. Miyawaki, M. Kawai, M. Oshima, and Y. Harada

Nanosc. Res. Lett. 11 (2016) 127 (1-7).

 

107. Redox Potential Paradox in NaxMO2 for Sodium-Ion Battery Cathodes

Y. Nanba, T. Iwao, B. M. de Boisse, E. Hosono, D. Asakura, H. Niwa, H. Kiuchi, J. Miyawaki, Y. Harada, M. Okubo, and A. Yamada,

Chem. Mater. 28 (2016) 1058-1065.

 

106. Characterization of nitrogen species incorporated into graphite using low energy nitrogen ion sputtering

H. Kiuchi, T. Kondo, M. Sakurai, D. Guo, J. Nakamura, H. Niwa, J. Miyawaki, M. Kawai, M. Oshima, and Y. Harada

Phys. Chem. Chem. Phys. 18 (2016) 458-465.

 

105. Electron-phonon coupling in the bulk of anatase TiO2 measured by RIXS

S. Moser, S. Fatale, P. Krüger, H. Berger, P. Bugnon, A. Magrez, H. Niwa, J. Miyawaki, Y. Harada, and M. Grioni

Phys. Rev. Lett., 115 (2015) 096404(1-5).

 

104. Enhancement in Kinetics of the Oxygen Reduction Reaction on a Nitrogen-Doped Carbon Catalyst by Introduction of Iron via Electrochemical Methods

J. Wu, D. Zhang, H. Niwa, Y. Harada, M. Oshima, H. Ofuchi, Y. Nabae, T. Okajima, and T. Ohsaka,

Langmuir, 31 (2015) 5529-5536

 

103. Active site formation mechanism of carbon-based oxygen reduction catalysts derived from a hyperbranched iron phthalocyanine polymer

Y. Hiraike, M. Saito, H. Niwa, M. Kobayashi, Y. Harada, M. Oshima, J. Kim, Y. Nabae, and M. Kakimoto,

Nanosc. Res. Lett. 10 (2015) 179 1-11.

 

102. First-Principles Investigation of Strong Excitonic Effects in Oxygen 1s X-Ray Absorption Spectra

Y. Noguchi, M. Hiyama, H. Akiyama, Y. Harada, and N. Koga

J. Chem. Theo. Comp. 11 (2015) 1668-1673.

 

101. Multi-phonon excitations in Fe 2p RIXS on Mg2FeH6

K. Kurita, D. Sekiba, I. Harayama, K. Chito, Y. Harada, H. Kiuchi, M. Oshima, S. Takagi, M. Matsuo, R. Sato, K. Aoki, and S. Orimo,

J. Phys. Soc. Jpn. 84 (2015) 043201(1-3).

 

100. X-ray Emission Spectroscopy of Bulk Liquid Water in "No-man's Land"

J. Sellberg, T. McQueen, H. Laksmono, S. Schreck, M. Beye, D. DePonte, B. O'Kennedy, D. Nordlund, R. Sierra, D. Schlesinger, T. Tokushima, S. Eckert, V. Segtnan, H. Ogasawara, K. Kubicek, S. Techert, U. Bergmann, G. Dakovski, W. Schlotter, Y. Harada, I. Zhovtobriukh, M. Bogan, P. Wernet, A. Föhlisch, L. Pettersson, and A. Nilsson,

J. Chem. Phys. 142 (2015) 044505(1-9).

 

99. Operando soft x-ray emission spectroscopy of LiMn2O4 thin film involving Li-ion extraction/insertion reaction

D. Asakura, E. Hosono, H. Niwa, H. Kiuchi, J. Miyawaki, Y. Nanba, M. Okubo, H. Matsuda, H. S. Zhou, M. Oshima and Y. Harada,

Electrochem. Commun. 50 (2015) 93-96.

 

98. Unveiling the impurity band induced ferromagnetism in the magnetic semiconductor (Ga,Mn)As

M. Kobayashi, I. Muneta, Y. Takeda, Y. Harada, A. Fujimori, J. Krempaský, T. Schmitt, S. Ohya, M. Tanaka, M. Oshima and V. N. Strocov,

Phys. Rev. B 89 (2014) 205204(1-8).

 

97. Electronic Excitations of a Magnetic Impurity State in the Diluted Magnetic Semiconductor (Ga,Mn)As

M. Kobayashi, H. Niwa, Y. Takeda, A. Fujimori, Y. Senba, H. Ohashi, A. Tanaka, S. Ohya, P. N. Hai, M. Tanaka, Y. Harada and M. Oshima,

Phys. Rev. Lett. 112 (2014) 107203(1-7).

 

96. Reabsorption of Soft X-Ray Emission at High X-Ray Free-Electron Laser Fluences

S. Schreck, M. Beye, J. A. Sellberg, T. McQueen, H. Laksmono, B. Kennedy, S. Eckert, D. Schlesinger, D. Nordlund, H. Ogasawara, R. G. Sierra, V. H. Segtnan, K. Kubicek, W. F. Schlotter, G. L. Dakovski, S. P. Moeller, U. Bergmann, S. Techert, L. G. M. Pettersson, P. Wernet, M. J. Bogan, Y. Harada, A. Nilsson and A. Föhlisch,

Phys. Rev. Lett. 113 (2014) 153002(1-6).

 

95. Spin and orbital magnetic moments of Fe in the n-type ferromagnetic semiconductor (In,Fe)As

M. Kobayashi, L. D. Anh, P. N. Hai, Y. Takeda, S. Sakamoto, T. Kadono, T. Okane, Y. Saitoh, H. Yamagami, Y. Harada, M. Oshima, M. Tanaka and A. Fujimori,

Appl. Phys. Lett. 105 (2014) 032403(1-4).

 

94. Solvation dependence of valence electronic states of water diluted in organic solvents probed by soft X-ray spectroscopy

T. Tokushima, Y. Horikawa, O. Takahashi, H. Arai, K. Sadakane, Y. Harada, Y. Takata and S. Shin,

Phys. Chem. Chem. Phys. 16 (2014) 10753-10761.

 

93. Distinguishing between High- and Low-Spin States for Divalent Mn in Mn-Based Prussian Blue Analogue by High-Resolution Soft X-ray Emission Spectroscopy

D. Asakura, Y. Nanba, M. Okubo, Y. Mizuno, H. Niwa, M. Oshima, H. Zhou, K. Okada and Y. Harada,

J. Phys. Chem. Lett. 5 (2014) 4008-4013.

 

92. New soft X-ray beamline BL07LSU at SPring-8

S. Yamamoto, Y. Senba, T. Tanaka, H. Ohashi, T. Hirono, H. Kimura, M. Fujisawa, J. Miyawaki, A. Harasawa, T. Seike, S. Takahashi, N. Nariyama, T. Matsushita, M. Takeuchi, T. Ohata, Y. Furukawa, K. Takeshita, S. Goto, Y. Harada, S. Shin, H. Kitamura, A. Kakizaki, M. Oshima and I. Matsuda,

J Synchrotron Rad 21 (2014) 352-365.

 

91. Iron-Nitrogen Coordination in Modified Graphene Catalyzes a Four-Electron-Transfer Oxygen Reduction Reaction

K. Kamiya, H. Koshikawa, H. Kiuchi, Y. Harada, M. Oshima, K. Hashimoto and S. Nakanishi,

ChemElectroChem 1 (2014) 877-884.

 

90. Development of an electromagnetic phase shifter using a pair of cut-core coils for a cross undulator

I. Matsuda, A. Kuroda, J. Miyawaki, Y. Kosegawa, S. Yamamoto, T. Seike, T. Bizen, Y. Harada, T. Tanaka and H. Kitamura,

Nucl. Instrum. Methods Phys. Res. A 767 (2014) 296-299.

 

89. Selective probing of OH-OD stretch vibrations in liquid water using resonant inelastic soft-x-ray scattering

Y. Harada, T. Tokushima, Y. Horikawa, O. Takahashi, H. Niwa, M. Kobayashi, M. Oshima, Y. Senba, H. Ohashi, K. T. Wikfeldt, A. Nilsson, L. G. M. Pettersson, and S. Shin,

Phys. Rev. Lett. 111 (2013) 193001(1-5).

 

88. Resonant inelastic X-ray scattering of liquid water

A. Nilsson, T. Tokushima, Y. Horikawa, Y. Harada, M. P. Ljungberg, S. Shin and L. G. M. Pettersson,

J. Electron Spectrosc. Relat. Phenom. 188 (2013) 84-100.

 

87. Probing carbon edge exposure of iron phthalocyanine-based oxygen reduction catalysts by soft X-ray absorption spectroscopy

H. Niwa, M. Saito, M. Kobayashi, Y. Harada, M. Oshima, S. Moriya, K. Matsubayashi, Y. Nabae, S. Kuroki, T. Ikeda, K. Terakura, J.-I. Ozaki and S. Miyata,

Journal of Power Sources 223 (2013) 30-35.

 

86. Operando soft X-ray emission spectroscopy of iron phthalocyanine-based oxygen reduction catalysts

H. Niwa, H. Kiuchi, J. Miyawaki, Y. Harada, M. Oshima, Y. Nabae and T. Aoki,

Electrochem. Commun. 35 (2013) 57-60.

 

85. Elucidation of Rh-induced in-gap states of Rh:SrTiO3 visible-light-driven photocatalyst by soft x-ray spectroscopy and first-principles calculations

S. Kawasaki, K. Akagi, K. Nakatsuji, S. Yamamoto, I. Matsuda, Y. Harada, J. Yoshinobu, F. Komori, R. Takahashi, M. Lippmaa, C. Sakai, H. Niwa, M. Oshima, K. Iwashina, A. Kudo,

J. Phys. Chem. C 116 (2012) 24445.

 

84. Atomic-scale characterization of nitrogen-doped graphite: Effects of dopant nitrogen on the local electronic structure of the surrounding carbon atoms

T. Kondo, S. Casolo, T. Suzuki, T. Shikano, M. Sakurai, Y. Harada,, M. Saito, M. Oshima, M. I. Trioni, G. F. Tantardini, and J. Nakamura

Phys. Rev. B 86 (2012) 035436.

 

83. Study on the oxygen adsorption property of nitrogen-containing metal-free carbon-based cathode catalysts for oxygen reduction reaction

H. Kiuchi, H. Niwa, M. Kobayashi, Y. Harada, M. Oshima, M. Chokai, Y. Nabae, S. Kuroki, M. Kakimoto, T. Ikeda, K. Terakura, and S. Miyta,

Electrochim. Acta 82 (2012) 291.

 

82. Indirect contribution of transition metal towards oxygen reduction reaction activity in iron

phthalocyanine-based carbon catalysts for polymer electrolyte fuel cells

M. Kobayashi, H. Niwa, Y. Harada, M. Oshima, H. Ofuchi, K. Terakura, T. Ikeda, Y. Koshigoe, J. Ozaki, S. Miyata

Electrochim. Acta 74 (2012) 254.

 

81. Platinum Oxidation Responsible for Degradation of Platinum-Cobalt Alloy Cathode Catalysts for Polymer Electrolyte Fuel Cells

S. Hidai, M. Kobayashi, H. Niwa, Y. Harada, M. Oshima, Y. Nakamori, T. Aoki

J. Power Sources 215 (2012) 233.

 

80. Polarization dependent resonant x-ray emission spectroscopy of D2O and H2O water; assignment of the local molecular orbital symmetry

T. Tokushima, Y. Horikawa, H. Arai, Y. Harada, O. Takahashi, L. Pettersson, A. Nilsson, S. Shin

J. Chem. Phys. 136 (2012) 044517.

 

79. Hydrogen bonding of water in 3-methylpyridine studied by O 1s X-ray emission and absorption spectroscopy

H. Arai, Y. Horikawa, K. Sadakane, T. Tokushima, Y. Harada, Y. Senba, H. Ohashi, Y. Takata, S. Shin,

Phys. Chem. Chem. Phys. 14 (2012) 1576.

 

78. Ultrahigh Resolution Soft X-Ray Emission Spectrometer at BL07LSU in SPring-8

Y. Harada, M. Kobayashi, H. Niwa, Y. Senba, H. Ohashi, T. Tokushima, Y. Horikawa, S. Shin, M. Oshima,

Rev. Sci. Instrum. 83 (2012) 013116.

 

77. Si 2p Core Level Shifts of the Epitaxial SiON Layer on a SiC(0001), Studied by Photoemissin Spectroscopy

T. Shirasawa, S. Tanaka, T. Muro, Y. Tamenori, Y. Harada, T. Tokushima, T. Kinoshita, S. Shin, T. Takahashi, H. Tochihara, Mater. Sci. Forum 675 (2011) 15.

 

76. Role of residual transition metal atoms in oxygen reduction reaction in cobalt phthalocyanine-based carbon cathode catalysts for polymer electrolyte fuel cell

M. Kobayashi, H. Niwa, Y. Harada, K. Horiba, M. Oshima, H. Ofuchi, K. Terakura, T. Ikeda, Y. Koshigoe, J. Ozaki, S. Miyata, S. Ueda, Y. Yamashita, H. Yoshikawa, K. Kobayashi,

J. Power Sources, 196 (2011) 8346-8351.

 

75. Changes in electronic states of platinum-cobalt alloy catalyst for polymer electrolyte fuel cells by potential cycling

S. Hidai, M. Kobayashi, H. Niwa, Y. Harada, M. Oshima, Y. Nakamori, T. Aoki,

J. Power Sources, 196 (2011) 8340-8345.

 

74. X-ray photoemission spectroscopy analysis of N-containing carbon-based cathode catalysts for polymer electrolyte fuel cells

H. Niwa, M. Kobayashi, K. Horiba, Y. Harada, M. Oshima, K. Terakura, T. Ikeda ,Y. Koshigoe, J. Ozaki, S. Miyata, S. Ueda, Y. Yamashita, H. Yoshikawa, K. Kobayashi,

J. Power Sources 196 (2011) 1006-1011.

 

73.Electronic Structures of Non-Pt Carbon Alloy Catalysts for Polymer Electrolyte Membrane Fuel Cells Revealed by Synchrotron Radiation Analyses

M. Oshima, H. Niwa, M. Saito, M. Kobayashi, K. Horiba, Y. Harada, K. Terakura, T. Ikeda, J. Ozaki, Y. Nabae and S. Miyata,

Mater. Res. Soc. Symp. Proc. 1318 (2011) 437.

 

72. Electronic structures of B 2p levels in homo-epitaxial growth boron-doped diamond by soft X-rays absorption spectroscopy

J. Nakamura, E. Kabasawa, Y. Harada, S. Iriyama, A. Kawano, T. Oguchi, K. Kuroki, Y. Takano, H. Kawarada,

Physica C 470 (2010) S671-S672.

 

71.Electronic structure of Pt-Co cathode catalysts in membrane electrolyte assembly observed by X-ray absorption fine structure spectroscopy with different probing depth

M. Kobayashi, H. Niwa, H. Ofuchi, S. Hidai, T. Aoki, Y. Harada and M. Oshima,

J. Electron Spectrosc. Relat. Phenom. 181, (2010) 239-241.

 

70.Polarization dependent soft X-ray emission spectroscopy of cobalt nano-islands on a nitrogen-adsorbed Cu(001) surface

K. Nakatsuji, Y. Takagi, Y. Yoshimoto, T. Iimori, K. Yaji, K. Tomatsu, Y. Harada, T. Takeuchi, T. Tokushima, Y. Takata, S. Shin, T. Ishikawa, F. Komori,

J. Electron. Spectrosc. Relat. Phenom. 181 (2010) 225-228.

 

69.High resolution X-ray emission spectroscopy of water and its assignment based on two structural motifs

T. Tokushima, Y. Harada, Y. Horikawa, O. Takahashi, Y. Senba, H. Ohashi, L. G. M. Pettersson, A. Nilsson, and S. Shin

J. Electron. Spectrosc. Relat. Phenom. 177 (2010) 192-205.

 

68.Reply to Soper et al.: Fluctuations in water around a bimodal distribution of local hydrogen-bonded structural motifs

C. Huang, K. T. Wikfeldt, T. Tokushima, D. Nordlund, Y. Harada, U. Bergmann, M. Niebuhr, T. M. Weiss, Y. Horikawa, M. Leetmaa, M. P. Ljungberg, O. Takahashi, A. Lenz, L. Ojamae, A. P. Lyubartsev, S. Shin, L. G. M. Pettersson, and A. Nilsson

Proc. Natl. Acad. Sci. USA 107 (2010) E45.

 

67.Electronic structures of imidazolium-based ionic liquids

K. Kanai, T. Nishi, T. Iwahashi, Y. Ouchi, Y. Harada, S. Shin, K. Seki,

J. Electron Spectrosc. Relat. Phenom. 174 (2009) 110-115.

 

66.Ligand energy controls the Heme-Fe valence in aqueous Myoglobins

Y. Harada, M. Taguchi, Y. Miyajima, T. Tokushima, Y. Horikawa, A. Chainani, Y. Shiro, Y. Senba, H. Ohashi, H. Fukuyama, S. Shin,

J. Phys. Soc. Jpn. 78 (2009) 044802(1-5).

 

65.Identification of valence electronic states of aqueous acetic acid in acid-base equilibrium using site-selective X-ray emission spectroscopy

Y. Horikawa, T. Tokushima, Y. Harada, O. Takahashi, A. Chainani, Y. Senba, H. Ohashi, A. Hiraya, S. Shin,

Phys. Chem. Chem. Phys. 11 (2009) 8676-8679

 

64.Co oxidation accompanied by degradation of Pt-Co alloy cathode catalysts in polymer electrolyte fuel cells

M. Kobayashi, S. Hidai, H. Niwa, Y. Harada, M. Oshima, Y. Horikawa, T. Tokushima, S. Shin, Y. Nakamori, T. Aoki,

Phys. Chem. Chem. Phys. 11 (2009) 8226-8230.

 

63.Defects generation in single-walled carbon nanotubes induced by soft X-ray illumination

Y. Mera, Y. Harada, S. Arima, K. Hata, S. Shin, K. Maeda,

Chem. Phys. Lett. 473 (2009) 138-141.

 

62.Atomic-layer-resolved bandgap structure of an ultrathin oxynitride-silicon film epitaxially grown on 6H-SiC(0001)

T. Shirasawa, K. Hayashi, H. Yoshida, S. Mizuno, S. Tanaka, T. Muro, Y. Tamenori, Y. Harada, T. Tokushima, Y. Horikawa, E. Kobayashi, T. Kinoshita, S. Shin, T. Takahashi, Y. Ando, K. Akagi, S. Tsuneyuki, H. Tochihara,

Phys. Rev. B 79 (2009) 241301(1-4).

 

61. The inhomogeneous structure of water at ambient conditions

C. Huang, K. T. Wikfeldt, T. Tokushima, D. Nordlund, Y. Harada, U. Bergmann, M. Niebuhr, T. M. Weiss, Y. Horikawa, M. Leetmaa, M. P. Ljungberg, O. Takahashi, A. Lenz, L. Ojamae, A. P. Lyubartsev, S. Shin, L. G. M. Pettersson, A. Nilsson,

Proc. Natl. Acad. Sci. USA 106 (2009) 15214-15218.

 

60.Selective observation of the two oxygen atoms at different sites in carboxyl group (-COOH) of liquid acetic acid

T. Tokushima, Y. Horikawa, Y. Harada, O. Takahashi, A. Hiraya and S. Shin,

Phys. Chem. Chem. Phys. 11 (2009) 1679-1682.

 

59.Characterization of Fe 3d states in CuFeS2 by resonant X-ray emission spectroscopy

K. Sato, Y. Harada, M. Taguchi, S. Shin, A. Fujimori,

Phys. Stat. Solidi A 206 (2009) 1096-1100.

 

58.X-ray absorption analysis of nitrogen contribution to oxygen reduction reaction in carbon alloy cathode catalysts for polymer electrolyte fuel cells

H. Niwa, K. Horiba, Y. Harada, M. Oshima, T. Ikeda, K. Terakura, J. Ozaki, S. Miyata,

J. Power Sources 187 (2009) 93-97.

 

57.Anomalous electronic structure of ionic liquids determined by soft x-ray emission spectroscopy: Contributions from the cations and anions to the occupied electronic structure

K. Kanai, T. Nishi, T. Iwahashi, Y. Ouchi, K. Seki, Y. Harada, S. Shin,

J. Chem. Phys. 129 (2008) 224507(1-5).

 

56.The role of a graphitic surface layer in electron-stimulated ordering in tetrahedral amorphous carbon films

S. Liang, T. Banno, Y. Mera, M. Kitajima, K. Ishioka, Y. Harada, Y. Kitajima, S. Shin, K. Maeda,

New Carbon Materials 23 (2008) 241-244.

 

55.σ-bonding contribution of a strong π-acceptor molecule: Surface chemical bond of SO2 on Ni(100)

T. Tokushima, Y. Harada, Y. Takata, K. Sodeyama, S. Tsuneyuki, M. Nagasono, Y. Kitajima, Y. Tamenori, H. Ohashi, A. Hiraya, S. Shin,

Phys. Rev. B 78 (2008) 085405(1-5).

 

54.High resolution x-ray emission spectroscopy of liquid water: The observation of two structural motifs

T. Tokushima, Y. Harada, O. Takahashi, Y. Senba, H. Ohashi, L. G. M. Pettersson, A. Nilsson, S. Shin,

Chem. Phys. Lett. (Frontiers Article) 460 (2008) 387-400.

 

53.Soft x-ray emission spectroscopy of Co nanoislands on a nitrogen-adsorbed Cu(001) surface

Y. Takagi, K. Nakatsuji, Y. Yoshimoto, T. Iimori, K. Yaji, K. Tomatsu, Y. Harada, T. Takeuchi, T. Tokushima, Y. Takata, S. Shin, T. Ishikawa, F. Komori,

Surf. Sci. 602 (2008) L65-L68.

 

52.Comment on Isotope and Temperature Effects in Liquid Water Probed by X-ray Absorption and Resonant X-ray Emission Spectroscopy

L. G. M. Pettersson, T. Tokushima, Y. Harada, O. Takahashi, S. Shin, A. Nilsson,

Phys. Rev. Lett. 100 (2008) 249801.

 

51.Recoil effects of photoelectrons in a solid

Y. Takata, Y. Kayanuma, M. Yabashi, K. Tamasaku, N. Nishino, D. Miwa, Y. Harada, K. Horiba, S. Shin, S. Tanaka, K. Ikenaga, K. Kobayashi, Y. Senba, H. Ohashi, and T. Ishikawa,

Phys. Rev. B 75, (2007) 233404(1-4).

 

50.Soft X-ray absorption and emission study of silicon oxynitride/Si(100) interface

Y. Yamashita, K. Oguchi, K. Mukai, J. Yoshinobu, Y. Harada, T. Tokushima, S. Shin, N. Tamura, H. Nohira, T. Hattori,

J. J. Appl. Phys. 46 (2007) L77-L79.

 

49.Structural change in amorphous carbon on core excitations induced by soft x-ray illumination

K. Maeda, S. Liang, Y. Harada, Y. Kitajima, S. Shin, Y. Mera,

Proc. SPIE, Vol. 6586 (2007) 65860C.

 

48.Electronic Structure of DNA Nucleobases and Their Dinucleotides Explored by Soft X-ray Spectroscopy

Y. Harada, T. Takeuchi, H. Kino, A. Fukushima, K. Takakura, K. Hieda, A. Nakao, S. Shin, H. Fukuyama

J. Phys. Chem: A,110 (2006) 13227-13231.

 

47.Dynamical changeover of core exciton state of graphite and resonant x-ray emission spectrum:From shallow to deep level with symmetry breaking

A. Yasui, Y. Kayanuma, S. Tanaka, Y. Harada,

Phys.Rev.B, 74 (2006) 205404(1-9).

 

46.Direct observation of site-specific valence electronic structure at the SiO2/Si interface

Y.Yamashita, S.Yamamoto, K.Mukai, J.Yoshinobu, Y.Harada, T.Tokushima, T.Takeuchi, Y.Takata, S.Shin, K.Akagi, S.Tsuneyuki

Phys.Rev.B, 73 (2006) 045336(1-4).

 

45.Effects of interface roughness on the local valence electronic structure at the SiO2/Si interface: soft x-ray absorption

Y.Yamashita, S.Yamamoto, K.Mukai, J.Yoshinobu, Y.Harada, T.Tokushima, Y.Takata, S.Shin

J. Phys. IV France, 132 (2006) 259-262.

 

44.Performance of a highly stabilized and high-resolution beamline BL17SU for advanced soft x-ray spectroscopy at SPring-8

H. Ohashi, Y. Senba, H. Kishimoto, T. Miura, E. Ishiguro, T. Takeuchi, M. Oura, K. Shirasawa, T. Tanaka, M. Takeuchi, K. Takeshita, S. Goto, S. Takahashi, H. Aoyagi, M. Sano, Y. Furukawa, T. Ohata, T. Matsushita, Y. Ishizawa, S. Taniguchi, Y. Asano, Y. Harada, T. Tokushima, K. Horiba, H. Kitamura, T. Ishikawa, S. Shin

AIP Conf. Proc., 879 (2006) 523.

 

43.Direct observation of site-specific valence electronic structure at SiO2/Si(111) interface

Y.Yamashita, S.Yamamoto, K.Mukai, J.Yoshinobu, Y.Harada, T.Tokushima, T.Takeuchi, Y.Takata, S.Shin, K.Akagi, S.Tsuneyuki

e-J Surf. Sci.Nanotech., 4 (2006) 280-284.

 

42.High performance slit-less spectrometer for soft x-ray emission spectroscopy

T.Tokushima, Y.Harada, H.Ohashi, Y.Senba, S.Shin

Rev.Sci.Instruments, 77 (2006) 063107(1-5).

 

41.Bulk band structure and fermi surface of nickel: a soft x-ray angle-resolved photoemission study

N.Kamakura, Y.Takata, T.Tokushima, Y.Harada, A.Chainani, K.Kobayashi, S.Shin

Phys.Rev.B, 74 (2006) 045127(1-9).

 

40.Intermolecular interaction by apical oxygen in titanyl phthalocyanine

Y.Harada, T.Tokushima, Y.Takata, N.Kamakura, T.Takeuchi, K.Kobayashi, Y.Shirota, S.Shin

J.J Appl.Phys, 44 (2005) L1147-1149.

 

39.Graphitization of tetrahedral amorphous carbon films incuced by core electron excitations

S.Liang, Y.Harada, S.Shin, Y.Kitajima, Y.Mera, K.Maeda

J.J Appl.Phys, 44 (2005) L1472-74.

 

38.Soft x-ray spectroscopy of diluted magnetic semiconductor Ga1-xMxN(M=Cr,Mn)

T.Takeuchi, Y.Harada, T.Tokushima, Y.Takata, A.Chainani, J.J.Kim, P.P.Chen, H.Makino, T.Hanada, T.Yao, T.Yamamoto, T.Tsukamoto, K.Kobayashi, S.Shin

J. Electron. Spectrosc. Relat. Phenom., 144-147 (2005) 707-710.

 

37.Local bonding structure in mechanically activated TiH2 and TiH2 plus graphite mixture

E.Z. Kurmaev, O. Morozova, T.I. Khomenko, C. Borchers, S.N. Nemnonov, Y. Harada, T. Tokushima, H. Osawa, T. Takeuchi, S. Shin

J. Alloys Compd., 395 (2005) 240-246.

 

36.Direct observation of a neutral Mn acceptor in Ga1-xMnxAs by resonant x-ray emission spectroscopy

Y.Ishiwata, T.Takeuchi, R.Eguchi, M.Watanabe, Y.Harada, K.Kanai, A.Chainani, M.Taguchi, S.Shin, M.C.Debnath, I.Souma, Y.Oka, T.Hayashi, Y.Hashimoto, S.Katsumoto, Y.Iye

Phys. Rev. B, 71 (2005) 121202-121205.

 

35.Iron nanoparticles in amorphous SiO2: X-ray emission and absorption spectra

E.Z. Kurmaev, D.A. Zatsepin, S.O. Cholakh, B. Schmidt, Y. Harada, T. Tokushima, H. Osawa, S. Shin, T. Takeuchi

Phys. Solid State, 47 (2005) 754-757.

 

34.Electronic structure characteristics of MBE (molecular beam epitaxy)-grown diluted magnetic semiconductor Ga1-xCrxN films

T.Takeuchi, M.Tagucih, Y.Harada, T.Tokushima, Y.Takata, A.Chainani, J.J.Kim, H.Makino, T.Yao, T.Tsukamoto, S.Shin, K. Kobayashi

J.J Appl.Phys., 44 (2005) L153-L155.

 

33.Dynamical symmetry breaking under core excitation in graphite: polarization correlation in soft x-ray recombination emission

Y.Harada, T.Tokushima, Y.Takata, T.Takeuchi, Y.Kitajima, S.Tanaka, Y.Kayanuma, S.Shin

Phys. Rev. Lett., 93 (2004) 017401-017403.

 

32.Polarization dependence in resonant soft X-ray emission spectroscopy of 3d transition metal compounds

Y.Harada, S.Shin

J. Electron. Spectrosc. Relat. Phenom., 136 (2004) 143-150.

 

31.Doping-dependent changes in nitrogen 2p states in the diluted magnetic semiconductor Ga1-xCrxN

T.Takeuchi, Y.Harada, T.Tokushima, M.Tagucih, Y.Takata, A.Chainani, J.J.Kim, H.Makino, T.Yao, T.Tsukamoto, S.Shin, K. Kobayashi

Phys. Rev. B, 70 (2004) 245323-245326.

 

30.A UHV apparatus for soft x-ray spetroscopy with symmetry selection for solids and surfaces

Y.Takata, T.Tokushima, Y.Harada, N.Kamakura, Y.Kitajima, M.Nagasono, Y.Tamenori, H.Ohashi, A.Hiraya, E.Ishiguro, S.Shin

AIP Conf. Proc., 705 (2004) 1186-1189.

 

29.Layer-dependent band dispersion and correlations using tunable soft x-ray ARPES

N.Kamakura, Y.Takata, T.Tokushima, Y.Harada, A.Chainani, K.Kobayashi, S.Shin

Europhysics Lett., 67 (2004) 240-246.

 

28.Resonant X-ray emission spectroscopy in scandium halides

M. Matubara, Y. Harada, S. Shin, T. Uozumi, A. Kotani

J. Phys. Soc. Jpn., 73 (2004) 711-718.

 

27.Electron　correlation energy of LaxSr1-xTiO3 by high-resolution soft-x-ray emission spectroscopy

T.Higuchi, T.Takeuchi, T.Tsukamoto, Y.Harada, Y.Taguchi, Y.Tokura, S.Shin

Nucl. Instrum. & Methods, 199 (2003) 386-390.

 

26.Unique identification of Zhang-Rice singlet excitation in Sr2CuO2Cl2 mediated by O 1s core hole;　Symmetry-selective resonant soft X-ray Raman scattering study

Y. Harada, K. Okada, R. Eguchi, A. Kotani, H. Takagi, T. Takeuchi, S. Shin

Phys. Rev. B, 66 (2002) 165104.

 

24.Design of a flat field spectrometer for soft X-ray emission spectroscopy

T. Tokushima, Y. Harada, M. Watanabe, Y. Takata, E. Ishiguro, A. Hiraya, S. Shin

Surf. Rev. & Lett., 9 (2002) 503-508.

 

23.Feasibility studies of the three-dimensional detector for soft x-ray emission spectroscopy

M. Oura, K. Kobayashi, M. Watanabe, Y. Harada, T. Suzuki, S. Shin, O. Jagutzki

Surf. Rev. & Lett., 9 (2002) 515-520.

 

22.Polarization dependence of resonant soft X-ray emission spectra in Ce compounds

M. Watanabe, Y. Harada, M. Nakazawa, Y. Ishiwata, R. Eguchi, T. Takeuchi, A. Kotani, S. Shin

Surf. Rev. & Lett., 9 (2002) 983-987.

 

21.Polarization dependence of resonant X-ray emission spectra in 3dn transition metal compounds with n=0,1,2,3

M.Matsubara, T.Uozumi, A.Kotani, Y.Harada, S.Shin

J. Phys. Soc. Jpn., 71 (2002) 347-356.

 

20.Manganese concentration and low-temperature annealing dependence of Ga1-xMnxAs by x-ray absorption spectroscopy

Y.Ishiwata, M.Watanabe, R.Eguchi, T.Takeuchi, Y.Harada, A.Chainani, S.Shin, T.Hayashi, Y,Hashimoto, S.Katsumoto, Y.Iye

Phys. Rev. B, 62 (2002) 233201.

 

19.p emission anomaly in the N 1s resonance emission from hexagonal BN:effects of the core hole potential

N.Miyata, M.Yanagihara, M.Watanabe, Y.Harada, S.Shin

J. Phys. Soc. Jpn., 71 (2002) 1761-1764.

 

18.Electronic structure of Bi4Ti3O12 thin film and single crystal determined by resonant soft-x-ray emission spectroscopy

T.Higuchi, K.Kudoh, T.Takeuchi, Y.Masuda, Y.Harada, S.Shin, T.Tsukamoto

J.J. Appl.Phys., 41 (2002) 7195-7197.

 

17.Polarization dependence of the soft-x-ray Raman scattering at the L edge of TiO2

Y. Harada, M. Watanabe, R. Eguchi, Y. Ishiwata, M. Matsubara, A. Kotani, A. Yagishita, S. Shin

J. Electron Spectrosc. Relat. Phenom., 114-116 (2001) 969-973.

 

16.Resonant soft x-ray emission spectroscopy of NiO across the Ni L2,3 thresholds

H. Ishii, Y. Ishiwata, R. Eguchi, Y. Harada, M. Watanabe, A. Chainani, S. Shin

J. Phys. Soc. Jpn., 70 (2001) 1813-1816.

 

15.Magnetism and metal-insulator transition in III-V based diluted magnetic semiconductors

S. Katsumoto, T. Hayashi, Y. Hashimoto, Y. Iye, Y. Ishiwata, M. Watanabe, R. Eguchi, T. Takeuchi, Y. Harada, S. Shin, K. Hirakawa

Materials Science & Engineering B-Solid State Materials for Advanced Technology, B84 (2001) 88-95.

 

14.Electronic structure of Bi4Ti3O12 thin filmby soft-x-ray emission spectroscopy

T.Higuchi, M.Tanaka, K.Kudoh, T.Takeuchi, Y.Harada, S.Shin, T.Tsukamoto

J.J. Appl.Phys., 40 (2001) 5803-5805.

 

13.Polarization dependence of the soft-x-ray Raman scattering at the L edge of TiO2

Y. Harada, T.Kinugasa, R. Eguchi,  M. Matsubara, A. Kotani, M.Watanabe, A. Yagishita, S. Shin

Phys.Rev.B, 61 (2000) 12854-12859.

 

12.High resolution soft X-ray absorption spectroscopy for the chemical state analysis of Mn

J.Kawai, Y.Mizutani, T.Sugimura, M.Sai, T.Higuchi, Y.Harada, A.Fukushima, M.Fujisawa, M.Watanabe, K.Maeda, S.Shin, Y.Gohshi

Spectr.Acta.B, 55 (2000) 1385-1395.

 

11.Polarization dependence of resonant X-ray emission spectra in early transition metal compounds

M.Matsubara, T.Uozumi, A.Kotani, Y.Harada, S.Shin

J. Phys. Soc. Jpn., 69 (2000) 1558-1565.

 

10.Soft-X-ray emission study on LaxSr1-xTiO3

T. Higuchi, T. Tsukamoto, M. Watanabe, Y. Harada, Y. Tezuka, Y. Tokura, S. Shin

Physica B, 281-282 (2000) 615-616.

 

9.Crystal-field splitting and the on-site Coulomb energy of LaxSr1-xTiO3 from resonant soft-x-ray emission spectroscopy

T. Higuchi, T. Tsukamoto, M. Watanabe, M.M. Grush, T.A. Callcott, R.C. Perera, D.L. Ederer, Y. Tokura, Y. Harada, Y. Tezuka, S. Shin

Phys. Rev. B, 60 (1999) 7711-7714.

 

8.Spectrometer for polarized soft X-ray Raman scattering

Y. Harada, H. Ishii, M. Fujisawa, Y. Tezuka, S. Shin, M. Watanabe, Y. Kitajima, A. Yagishita

J. Sync. Rad., 5 (1998) 1013-1015.

 

7.Mn La and F Ka resonant X-ray fluorescence spectroscopy of MnF2

J. Kawai, T. Yamamoto, Y. Harada, S. Shin

J. Sync. Rad., 5 (1998) 1067-1068.

 

6.Soft X-ray emission spectroscopy of early transition metal compounds

S. Shin, M. Fujisawa, H. Ishii, Y. Harada, M. Watanabe, M.M. Grush, T.A. Callcott, R.C.C. Perera, E.Z. Kurmaev, A. Moewes, R. Winarski, S. Stadler, D.L. Ederer

J. Electron. Spectrosc. Relat. Phenom., 92 (1998) 197-205.

 

5.Soft X-ray emission spectroscopy of NiAs-type MnTe at the Mn 2p core threshold

T. Kotsugi, H. Sato, S. Senba, H. Okuda, Y. Ueda, M. Taniguchi, Y. Harada, S. Shin, A. Tanaka, T. Jo

J. Electron. Spectrosc. Relat. Phenom., 88-91 (1998) 293-296.


4.Electronic structure of Sr2RuO4: X-ray fluorescence emission study

E.Z. Kurmaev, S. Stadler, D.L. Ederer, Y. Harada, S. Shin, M.M. Grush, T.A. Callcott, R.C.C. Perera, D.A. Zatsepin, N. Ovechkina, M. Kasai, Y. Tokura, T. Takahashi, K. Chandrasekaran, R. Vijayaraghavan, U.V. Varadaraju

Phys. Rev. B, 57 (1998) 1558-1562.

 

3.Fluorine K alpha X-ray fluorescence spectra of MnF2 excited at threshold

J. Kawai, T. Yamamoto, Y. Harada, S. Shin

Sol.State Commun., 105 (1998) 381-385.

 

2.Relaxation process of the excited state and selection rule in the soft X-ray emission of Si and cBN

S. Shin, A. Agui, Y. Harada

J. Sync. Rad., 4 (1997) 256-260.

 

1.Observation of the surface 4f state of CePd7 by means of the resonant -inverse-photoemission study at the Ce 4d absorption edge

K. Kanai, Y. Tezuka, M. Fujisawa, Y. Harada, S. Shin, G. Schmerber, J.P. Kappler, J.C. Parlebas, A. Kotani

Phys. Rev. B, 55 (1997) 2623-2627.