Details of the Researcher

PHOTO

Kazuto Akagi
Section
Advanced Institute for Materials Research
Job title
Associate Professor
Degree

  • 博士（理学）（東京大学）

Professional Memberships 3

  • THE JAPAN SOCIETY OF APPLIED PHYSICS

  • THE PHYSICAL SOCIETY OF JAPAN

  • The Japan Society of Vacuum and Surface Science

Research Interests 3

  • topological data analysis

  • first-principles calculation

  • surface science

Research Areas 4

  • Nanotechnology/Materials / Nanostructure chemistry /

  • Informatics / Computational science /

  • Nanotechnology/Materials / Nanostructure physics /

  • Natural sciences / Semiconductors, optical and atomic physics /

Papers 65

  1. Surface melting–driven hydrogen absorption for high-pressure polyhydride synthesis

    Ryuhei Sato, Lewis J. Conway, Di Zhang, Chris J. Pickard, Kazuto Akagi, Kartik Sau, Hao Li, Shin-ichi Orimo

    Proceedings of the National Academy of Sciences　2025/06/03

    DOI： 10.1073/pnas.2413480122 　

  2. Linear regression model for metal–organic frameworks with CO2 adsorption based on topological data analysis Peer-reviewed

    Kazuto Akagi, Hisashi Naito, Takafumi Saikawa, Motoko Kotani, Hirofumi Yoshikawa

    Scientific Reports　14　(1)　2024/05/26

    Publisher: Springer Science and Business Media LLC

    DOI： 10.1038/s41598-024-62858-7 　

    eISSN： 2045-2322

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    Abstract Metal–organic frameworks (MOFs), self-assembled porous materials synthesized from metal ions and organic ligands, are promising candidates for the direct capture of CO2 from the atmosphere. In this work, we developed a regression model to predict the optimal component of the MOF that governs the amount of CO2 adsorption per volume based on experimentally observed adsorption and structure data combined with MOF adsorption sites. The structural descriptors were generated by topological data analysis with persistence diagrams, an advanced mathematical method for quantifying the rings and cavities within the MOF. This enables us to analyze direct effects and significance of the geometric structure of the MOF on the efficiency of CO2 adsorption in a novel way. The proposed approach is proved to be highly correlated with experimental data and thus offers an effective screening tool for MOFs with optimized structures.

  3. Topological data analysis of TEM-based structural features affecting the thermal conductivity of amorphous Ge Peer-reviewed

    Yen-Ju Wu, Kazuto Akagi, Masahiro Goto, Yibin Xu

    International Journal of Heat and Mass Transfer　221　125012-125012　2024/04

    Publisher: Elsevier BV

    DOI： 10.1016/j.ijheatmasstransfer.2023.125012 　

    ISSN： 0017-9310

  4. Finding “Trigger Sites” of Reactions Among Heterogeneous Materials from X-ray Microscopic Big Data Using Persistent Homology Peer-reviewed

    Masao Kimura, Ippei Obayashi, Daiki Kido, Yasuhiro Niwa, Xichan Gao, Kazuto Akagi

    The Minerals, Metals & Materials Series　784-792　2024/02/07

    Publisher: Springer Nature Switzerland

    DOI： 10.1007/978-3-031-50349-8_67 　

    ISSN： 2367-1181

    eISSN： 2367-1696

  5. Topological Data analysis of Ion Migration Mechanism Peer-reviewed

    Ryuhei Sato, Kazuto Akagi, Shigeyuki Takagi, Kartik Sau, Kazuaki Kisu, Hao Li, Shin-ichi Orimo

    The Journal of Chemical Physics　158　(14)　2023/04/13

    Publisher: AIP Publishing

    DOI： 10.1063/5.0143387 　

    ISSN： 0021-9606

    eISSN： 1089-7690

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    Topological data analysis based on persistent homology has been applied to the molecular dynamics simulation for the fast ion-conducting phase (α-phase) of AgI to show its effectiveness on the ion migration mechanism analysis. Time-averaged persistence diagrams of α-AgI, which quantitatively record the shape and size of the ring structures in the given atomic configurations, clearly showed the emergence of the four-membered rings formed by two Ag and two I ions at high temperatures. They were identified as common structures during the Ag ion migration. The averaged potential energy change due to the deformation of the four-membered ring during Ag migration agrees well with the activation energy calculated from the conductivity Arrhenius plot. The concerted motion of two Ag ions via the four-membered ring was also successfully extracted from molecular dynamics simulations by our approach, providing new insight into the specific mechanism of the concerted motion.

  6. Elucidation of local structure deformation in κ-(BEDT-TTF)2Cu [N(CN)2]Br by x-ray fluorescence holography

    Artoni Kevin R. Ang, Riho Marumi, Ayana Sato-Tomita, Koji Kimura, Naohisa Happo, Kazuto Akagi, Takahiko Sasaki, Kouichi Hayashi

    Physical Review B　103　(21)　2021/06/01

    DOI： 10.1103/PhysRevB.103.214106 　

    ISSN： 2469-9950

    eISSN： 2469-9969

  7. Visible fingerprint of X-ray images of epoxy resins using singular value decomposition of deep learning features

    Avalos, E., Akagi, K., Nishiura, Y.

    Computational Materials Science　186　2021

    DOI： 10.1016/j.commatsci.2020.109996 　

    ISSN： 0927-0256

  8. Bridging a mesoscopic inhomogeneity to macroscopic performance of amorphous materials in the framework of the phase field modeling

    Avalos, E., Xie, S., Akagi, K., Nishiura, Y.

    Physica D: Nonlinear Phenomena　409　2020

    DOI： 10.1016/j.physd.2020.132470 　

    ISSN： 0167-2789

  9. Granular Barium Titanate Nanowire-Based Adsorbents for the Removal of Strontium Ions from Contaminated Water Peer-reviewed

    Teppei Saito, Norihito Shiraiwa, Yuta Morioka, Kazuto Akagi, Koji S. Nakayama, Tadafumi Adschiri, Naoki Asao

    ACS Applied Nano Materials　2　(11)　6793-6797　2019/11/22

    Publisher: American Chemical Society (ACS)

    DOI： 10.1021/acsanm.9b01737 　

    ISSN： 2574-0970

    eISSN： 2574-0970

  10. Strong metal-metal interaction and bonding nature in metal/oxide interfaces with large mismatches Peer-reviewed

    Li Hongping, Saito Mitsuhiro, Chen Chunlin, Inoue Kazutoshi, Akagi Kazuto, Ikuhara Yuichi

    ACTA MATERIALIA　179　237-246　2019/10/15

    DOI： 10.1016/j.actamat.2019.08.018 　

    ISSN： 1359-6454

  11. Reorientational motion and Li+-ion transport in Li2B12H12 system: Molecular dynamics study

    Kartik Sau, Tamio Ikeshoji, Sangryun Kim, Shigeyuki Takagi, Kazuto Akagi, Shin-ichi Orimo

    PHYSICAL REVIEW MATERIALS　3　(7)　2019/07

    DOI： 10.1103/PhysRevMaterials.3.075402 　

    ISSN： 2475-9953

  12. Complementary Design for Pairing between Two Types of Nanoparticles Mediated by a Bispecific Antibody: Bottom-Up Formation of Porous Materials from Nanoparticles. International-journal Peer-reviewed

    Teppei Niide, Noriyoshi Manabe, Hikaru Nakazawa, Kazuto Akagi, Takamitsu Hattori, Izumi Kumagai, Mitsuo Umetsu

    Langmuir : the ACS journal of surfaces and colloids　35　(8)　3067-3076　2019/02/26

    DOI： 10.1021/acs.langmuir.8b03687 　

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    Recent advances in biotechnology have enabled the generation of antibodies with high affinity for the surfaces of specific inorganic materials. Herein, we report the synthesis of functional materials from multiple nanomaterials by using a small bispecific antibody recombinantly constructed from gold-binding and ZnO-binding antibody fragments. The bispecific antibody-mediated spontaneous linkage of gold and ZnO nanoparticles forms a binary gold-ZnO nanoparticle composite membrane. The relatively low melting point of the gold nanoparticles and the solubility of ZnO in dilute acidic solution then allowed for the bottom-up synthesis of a nanoporous gold membrane by means of a low-energy, low-environmental-load protocol. The nanoporous gold membrane showed high catalytic activity for the reduction of p-nitrophenol to p-aminophenol by sodium borohydride. Here, we show the potential utility of nanoparticle pairing mediated by bispecific antibodies for the bottom-up construction of nanostructured materials from multiple nanomaterials.

  13. Local chemical ordering within the incubation period as a trigger for nanocrystallization of a highly supercooled Ti-based liquid Peer-reviewed

    Wang Zhi, Chen Chunlin, Ketov Sergey V, Akagi Kazuto, Tsarkov Andrey A, Ikuhara Yuichi, Louzguine-Luzgin Dmitri V

    MATERIALS & DESIGN　156　504-513　2018/10/15

    DOI： 10.1016/j.matdes.2018.07.013 　

    ISSN： 0264-1275

    eISSN： 1873-4197

  14. Dealloying-oxidation Technique as a Powerful Synthetic Tool for Sodium Titanate Nanowires with High Ion-exchange Ability Peer-reviewed

    Teppei Saito, Man Zhang, Rahul D. Kavthe, Kazuto Akagi, Koji S. Nakayama, Tadafumi Adschiri, Naoki Asao

    CHEMISTRY LETTERS　46　(12)　1825-1827　2017/12

    DOI： 10.1246/cl.170887 　

    ISSN： 0366-7022

    eISSN： 1348-0715

  15. First-principles investigation of local structure deformation induced by x-ray irradiation in kappa-(BEDT-TTF)(2)Cu[N(CN)(2)]Br Peer-reviewed

    Lijing Kang, Kazuto Akagi, Kouichi Hayashi, Takahiko Sasaki

    PHYSICAL REVIEW B　95　(21)　2017/06

    DOI： 10.1103/PhysRevB.95.214106 　

    ISSN： 2469-9950

    eISSN： 2469-9969

  16. The chemistry of simple alkene molecules on Si(100)c(4 x 2): The mechanism of cycloaddition and their selectivities Peer-reviewed

    Kazuto Akagi, Jun Yoshinobu

    SURFACE SCIENCE　652　304-311　2016/10

    DOI： 10.1016/j.susc.2016.03.027 　

    ISSN： 0039-6028

    eISSN： 1879-2758

  17. Fast Calculation Algorithm Using Barton's Method for Reconstructing Three-Dimensional Atomic Images from X-ray Fluorescence Holograms Peer-reviewed

    Tomohiro Matsushita, Atsushi Kubota, Naohisa Happo, Kazuto Akagi, Natsuhiko Yoshinaga, Kouichi Hayashi

    ZEITSCHRIFT FUR PHYSIKALISCHE CHEMIE-INTERNATIONAL JOURNAL OF RESEARCH IN PHYSICAL CHEMISTRY & CHEMICAL PHYSICS　230　(4)　449-455　2016/04

    DOI： 10.1515/zpch-2015-0652 　

    ISSN： 0942-9352

  18. Unification of the low-energy excitation peaks in the heat capacity that appears in clathrates Peer-reviewed

    Jiazhen Wu, Kazuto Akagi, Jingtao Xu, Hidekazu Shimotani, Khuong K. Huynh, Katsumi Tanigaki

    PHYSICAL REVIEW B　93　(9)　2016/03

    DOI： 10.1103/PhysRevB.93.094303 　

    ISSN： 2469-9950

    eISSN： 2469-9969

  19. 19pBL-14 Anharmonic phonons viewed from van der Waals potentials in cage structure compounds

    Wu Jiazhen, Akagi Kazuto, Shimotani Hidekazu, Huynh Khuong K., Tanigaki Katsumi

    Meeting Abstracts of the Physical Society of Japan　71　2018-2018　2016

    Publisher: The Physical Society of Japan (JPS)

    DOI： 10.11316/jpsgaiyo.71.1.0_2018 　

    ISSN： 2189-079X

  20. Characteristics of Lithium Ions and Superoxide Anions in EMI-TFSI and Dimethyl Sulfoxide Peer-reviewed

    Sun-ho Jung, Filippo Federici Canova, Kazuto Akagi

    JOURNAL OF PHYSICAL CHEMISTRY A　120　(3)　364-371　2016/01

    DOI： 10.1021/acs.jpca.5b09692 　

    ISSN： 1089-5639

  21. Self-Assembly Strategy for Fabricating Connected Graphene Nanoribbons Peer-reviewed

    Patrick Han, Kazuto Akagi, Filippo Federici Canova, Ryota Shimizu, Hiroyuki Oguchi, Susumu Shiraki, Paul S. Weiss, Naoki Asao, Taro Hitosugi

    ACS NANO　9　(12)　12035-12044　2015/12

    DOI： 10.1021/acsnano.5b04879 　

    ISSN： 1936-0851

    eISSN： 1936-086X

  22. Spontaneous formation of suboxidic coordination around Co in ferromagnetic rutile Ti0.95Co0.05O2 film Peer-reviewed

    Wen Hu, Kouichi Hayashi, Tomoteru Fukumura, Kazuto Akagi, Masaru Tsukada, Naohisa Happo, Shinya Hosokawa, Kenji Ohwada, Masamitu Takahasi, Motohiro Suzuki, Masashi Kawasaki

    APPLIED PHYSICS LETTERS　106　(22)　2015/06

    DOI： 10.1063/1.4921847 　

    ISSN： 0003-6951

    eISSN： 1077-3118

  23. Reply to "Comment on 'Bottom-Up Graphene-Nanoribbon Fabrication Reveals Chiral Edges and Enantio selectivity'" Peer-reviewed

    Patrick Han, Kazuto Akagi, Filippo Federici Canova, Hirotaka Mutoh, Susumu Shiraki, Katsuya Iwaya, Paul S. Weiss, Naoki Asao, Taro Hitosugi

    ACS NANO　9　(4)　3404-3405　2015/04

    DOI： 10.1021/acsnano.5b01687 　

    ISSN： 1936-0851

    eISSN： 1936-086X

  24. Graphene integration by molecular assembly Peer-reviewed

    Patrick Han, Kazuto Akagi, Filippo Federici Canova, Hirotaka Mutoh, Susumu Shiraki, Katsuya Iwaya, Paul Weiss, Naoki Asao, Taro Hitosugi

    ABSTRACTS OF PAPERS OF THE AMERICAN CHEMICAL SOCIETY　249　2015/03

    ISSN： 0065-7727

  25. Identification of Peptide Adsorbates for Strong Nanoparticle-Nanoparticle Binding by Lattice Protein Simulations Peer-reviewed

    Daniel M. Packwooda, Kazuto Akagi, Mitsuo Umetsu

    Materials Discovery　1　2-9　2015

    DOI： 10.1016/j.md.2015.10.003 　

    ISSN： 2352-9245

  26. 18pDA-14 Unified picture of low-energy excitation peaks associated with anharmonic phonons in cage-structured materials with d- and f-elements

    Tanigaki K., Wu Jiazhen, Shimotani H., Akagi K.

    Meeting Abstracts of the Physical Society of Japan　70　2036-2036　2015

    Publisher: The Physical Society of Japan (JPS)

    DOI： 10.11316/jpsgaiyo.70.2.0_2036 　

    ISSN： 2189-079X

  27. 18aAF-4 Unification of boson peaks in clathrate compounds

    Wu Jiazhen, Akagi Kazuto, Shimotani Hidekazu, Tanigaki Katsumi

    Meeting Abstracts of the Physical Society of Japan　70　1603-1603　2015

    Publisher: The Physical Society of Japan (JPS)

    DOI： 10.11316/jpsgaiyo.70.2.0_1603 　

    ISSN： 2189-079X

  28. Imaging the Evolution of d States at a Strontium Titanate Surface Peer-reviewed

    Ikutaro Hamada, Ryota Shimizu, Takeo Ohsawa, Katsuya Iwaya, Tomihiro Hashizume, Masaru Tsukada, Kazuto Akagi, Taro Hitosugi

    JOURNAL OF THE AMERICAN CHEMICAL SOCIETY　136　(49)　17201-17206　2014/12

    DOI： 10.1021/ja509231w 　

    ISSN： 0002-7863

  29. Atomic and electronic structure of the SrNbO3/SrNbO3.4 interface Peer-reviewed

    Chunlin Chen, Shuhui Lv, Zhongchang Wang, Kazuto Akagi, Frank Lichtenberg, Yuichi Ikuhara, Johannes Georg Bednorz

    APPLIED PHYSICS LETTERS　105　(22)　2014/12

    DOI： 10.1063/1.4902970 　

    ISSN： 0003-6951

    eISSN： 1077-3118

  30. Electronic Structure and Photoelectrochemical Properties of an Ir-Doped SrTiO3 Photocatalyst Peer-reviewed

    Seiji Kawasaki, Ryota Takahashi, Kazuto Akagi, Jun Yoshinobu, Fumio Komori, Koji Horiba, Hiroshi Kumigashira, Katsuya Iwashina, Akihiko Kudo, Mikk Lippmaa

    JOURNAL OF PHYSICAL CHEMISTRY C　118　(35)　20222-20228　2014/09

    DOI： 10.1021/jp5062573 　

    ISSN： 1932-7447

  31. Bottom-Up Graphene-Nanoribbon Fabrication Reveals Chiral Edges and Enantioselectivity Peer-reviewed

    Patrick Han, Kazuto Akagi, Filippo Federici Canova, Hirotaka Mutoh, Susumu Shiraki, Katsuya Iwaya, Paul S. Weiss, Naoki Asao, Taro Hitosugi

    ACS NANO　8　(9)　9181-9187　2014/09

    DOI： 10.1021/nn5028642 　

    ISSN： 1936-0851

    eISSN： 1936-086X

  32. Enhanced Supercapacitor Performance of MnO2 by Atomic Doping Peer-reviewed

    Jianli Kang, Akihiko Hirata, Lijing Kang, Xianmin Zhang, Ying Hou, Luyang Chen, Cheng Li, Takeshi Fujita, Kazuto Akagi, Mingwei Chen

    ANGEWANDTE CHEMIE-INTERNATIONAL EDITION　52　(6)　1664-1667　2013

    DOI： 10.1002/anie.201208993 　

    ISSN： 1433-7851

  33. Elucidation of Rh-Induced In-Gap States of Rh:SrTiO3 Visible-Light-Driven Photocatalyst by Soft X-ray Spectroscopy and First-Principles Calculations Peer-reviewed

    Seiji Kawasaki, Kazuto Akagi, Kan Nakatsuji, Susumu Yamamoto, Iwao Matsuda, Yoshihisa Harada, Jun Yoshinobu, Fumio Komori, Ryota Takahashi, Mikk Lippmaa, Chikako Sakai, Hideharu Niwa, Masaharu Oshima, Katsuya Iwashina, Akihiko Kudo

    JOURNAL OF PHYSICAL CHEMISTRY C　116　(46)　24445-24448　2012/11

    DOI： 10.1021/jp3082529 　

    ISSN： 1932-7447

    eISSN： 1932-7455

  34. 26pTH-4 The electronic states and the configuration of F_4-TCNQ on the ethylene terminated Si(100) substrate.

    Mukai K., Kameshima K., Murase K., Koitaya T., Shimizu S., Yoshimoto S., Akagi K., Yoshinobu J.

    Meeting Abstracts of the Physical Society of Japan　66.1.4　920　2011

    Publisher: The Physical Society of Japan

    DOI： 10.11316/jpsgaiyo.66.1.4.0_920_2 　

    eISSN： 2189-0803

  35. Towards the microscopic understanding of solid/liquid interfaces Peer-reviewed

    Kazuto Akagi

    BURIED INTERFACE SCIENCES WITH X-RAYS AND NEUTRONS 2010　24　2011

    DOI： 10.1088/1757-899X/24/1/012001 　

    ISSN： 1757-8981

  36. Molecular orbital calculation of biomolecules with fragment molecular orbitals Peer-reviewed

    Shinji Tsuneyuki, Tomoki Kobori, Kazuto Akagi, Keitaro Sodeyama, Kiyoyuki Terakura, Hidetoshi Fukuyama

    CHEMICAL PHYSICS LETTERS　476　(1-3)　104-108　2009/07

    DOI： 10.1016/j.cplett.2009.05.069 　

    ISSN： 0009-2614

  37. 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, S. Shin, T. Takahashi, Y. Ando, K. Akagi, K. Akagi, S. Tsuneyuki, S. Tsuneyuki, H. Tochihara

    Physical Review B - Condensed Matter and Materials Physics　79　(24)　2009/06/01

    DOI： 10.1103/PhysRevB.79.241301 　

    ISSN： 1098-0121

  38. Electron Transport Properties and Dielectric Breakdown of Alkyl Monolayers Chemisorbed on a Highly Doped n-Type Si(111) Surface Peer-reviewed

    Masayuki Furuhashi, Ayako Omura, Yoshiyuki Yamashita, Kozo Mukai, Jun Yoshinobu, Kazuto Akagi, Shinji Tsuneyuki

    JAPANESE JOURNAL OF APPLIED PHYSICS　48　(5)　2009/05

    DOI： 10.1143/JJAP.48.055003 　

    ISSN： 0021-4922

  39. Long-range proton transport for the water reaction on Si(001): Study of hydrogen-bonded systems with a model liquid-solid interface Peer-reviewed

    Hiroyuki S. Kato, Kazuto Akagi, Shinji Tsuneyuki, Maki Kawai

    JOURNAL OF PHYSICAL CHEMISTRY C　112　(33)　12879-12886　2008/08

    DOI： 10.1021/jp801598s 　

    ISSN： 1932-7447

  40. Regioselective cycloaddition reaction of alkene molecules with the asymmetric dimer on Si(100)c(4x2) Peer-reviewed

    Kazuhiro Oguchi, Masashi Nagao, Hirobumi Umeyama, Tetsuo Katayama, Yoshiyuki Yamashita, Kozo Mukai, Jun Yoshinobu, Kazuto Akagi, Shinji Tsuneyuki

    JOURNAL OF THE AMERICAN CHEMICAL SOCIETY　129　(5)　1242-1245　2007/02

    DOI： 10.1021/ja066285i 　

    ISSN： 0002-7863

  41. Formation of dihydride chains on H-terminated Si(100)-2x1 surfaces: Scanning tunneling microscopy and first-principles calculations Peer-reviewed

    Suwa, Yuji, Fujimori, Masaaki, Heike, Seiji, Terada, Yasuhiko, Yoshimoto, Yoshihide, Akagi, Kazuto, Sugino, Osamu, Hashizume, Tomihiro

    PHYSICAL REVIEW B　74　(20)　0-0　2006/11

    Publisher: AMERICAN PHYSICAL SOC

    DOI： 10.1103/PhysRevB.74.205308 　

    ISSN： 1098-0121

  42. Formation of dihydride chains on H-terminated Si(100)-2x1 surfaces: Scanning tunneling microscopy and first-principles calculations Peer-reviewed

    Yuji Suwa, Masaaki Fujimori, Seiji Heike, Yasuhiko Terada, Yoshihide Yoshimoto, Kazuto Akagi, Osamu Sugino, Tomihiro Hashizume

    PHYSICAL REVIEW B　74　(20)　2006/11

    DOI： 10.1103/PhysRevB.74.205308 　

    ISSN： 2469-9950

    eISSN： 2469-9969

  43. Theoretical study on atomic structures of thermally grown silicon oxide/silicon interfaces

    Hiroyuki Kageshima, Masashi Uematsu, Kazuto Akagi, Shinji Tsuneyuki, Toru Akiyama, Kenji Shiraishi

    e-Journal of Surface Science and Nanotechnology　4　584-587　2006/08/10

    DOI： 10.1380/ejssnt.2006.584 　

    ISSN： 1348-0391

  44. Mechanism of oxide deformation during silicon thermal oxidation Peer-reviewed

    H. Kageshima, M. Uematsu, K. Akagi, S. Tsuneyuki, T. Akiyama, K. Shiraishi

    Physica B: Condensed Matter　376-377　(1)　407-410　2006/04/01

    Publisher: Elsevier BV

    DOI： 10.1016/j.physb.2005.12.105 　

    ISSN： 0921-4526

  45. First principles study of dihydride chains on H-terminated Si(100)-2×1 surface Peer-reviewed

    Yuji Suwa, Masaaki Fujimori, Seiji Heike, Yasuhiko Terada, Yoshihide Yoshimoto, Kazuto Akagi, Osamu Sugino, Tomihiro Hashizume

    Japanese Journal of Applied Physics, Part 1: Regular Papers and Short Notes and Review Papers　45　(3 B)　2200-2203　2006/03/27

    DOI： 10.1143/JJAP.45.2200 　

    ISSN： 0021-4922 1347-4065

  46. Direct observation of the site-specific valence electronic structure at SiO<inf>2</inf>/Si(111) interface

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

    e-Journal of Surface Science and Nanotechnology　4　280-284　2006/03/24

    DOI： 10.1380/ejssnt.2006.280 　

    ISSN： 1348-0391

  47. Direct observation of site-specific valence electronic structure at the Si O2 Si interface

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

    Physical Review B - Condensed Matter and Materials Physics　73　(4)　2006/02/28

    DOI： 10.1103/PhysRevB.73.045336 　

    ISSN： 1098-0121

  48. Transport mechanism of interfacial network forming atoms during silicon oxidation Peer-reviewed

    Hiroyuki Kageshima, Masahi Uematsu, Kazuto Akagi, Shinji Tsuneyuki, Toru Akiyama, Kenji Shiraishi

    Japanese Journal of Applied Physics, Part 1: Regular Papers and Short Notes and Review Papers　45　(2 A)　694-699　2006/02/08

    DOI： 10.1143/JJAP.45.694 　

    ISSN： 0021-4922

  49. Interaction of condensed water molecules with hydroxyl and hydrogen groups on Si(001) Peer-reviewed

    HS Kato, M Kawai, K Akagi, S Tsuneyuki

    SURFACE SCIENCE　587　(1-2)　34-40　2005/08

    DOI： 10.1016/j.susc.2005.04.032 　

    ISSN： 0039-6028

  50. First-principles study of excess Si-atom stability around Si-oxide/Si interfaces Peer-reviewed

    Hiroyuki Kageshima, Masashi Uematsu, Kazuto Akagi, Shinji Tsuneyuki, Toru Akiyama, Kenji Shiraishi

    AIP Conference Proceedings　772　389-390　2005/06/30

    DOI： 10.1063/1.1994149 　

    ISSN： 0094-243X 1551-7616

  51. Nanotube-based molecular magnets with spin-polarized edge states Peer-reviewed

    Yusuke Higuchi, Koichi Kusakabe, Naoshi Suzuki, Shinji Tsuneyuki, Jun Yamauchi, Kazuto Akagi, Yoshihide Yoshimoto

    Journal of Physics Condensed Matter　16　(48)　S5689-S5692　2004/12/08

    DOI： 10.1088/0953-8984/16/48/028 　

    ISSN： 0953-8984

  52. Theoretical study of excess Si emitted from Si-oxide/Si interfaces Peer-reviewed

    Hiroyuki Kageshima, Masahi Uematsu, Kazuto Akagi, Shinji Tsuneyuki, Toru Akiyama, Kenji Shiraishi

    Japanese Journal of Applied Physics, Part 1: Regular Papers and Short Notes and Review Papers　43　(12)　8223-8226　2004/12

    DOI： 10.1143/JJAP.43.8223 　

    ISSN： 0021-4922

  53. Precursor mediated cycloaddition reaction of ethylene to the Si(100)c(4 x 2) surface Peer-reviewed

    M Nagao, H Umeyama, K Mukai, Y Yamashita, J Yoshinobu, K Akagi, S Tsuneyuki

    JOURNAL OF THE AMERICAN CHEMICAL SOCIETY　126　(32)　9922-9923　2004/08

    DOI： 10.1021/ja047426o 　

    ISSN： 0002-7863

  54. Structural and chemical property of unsaturated cyclic-hydrocarbon molecules regularly chemisorbed on Si(001) surface Peer-reviewed

    K Akagi, S Tsuneyuki, Y Yamashita, K Hamaguchi, J Yoshinobu

    APPLIED SURFACE SCIENCE　234　(1-4)　162-167　2004/07

    DOI： 10.1016/j.apsusc.2004.05.054 　

    ISSN： 0169-4332

  55. Magnetic properties of nanographite with modified zigzag edges Peer-reviewed

    Masanori Maruyama, Koichi Kusakabe, Shinji Tsuneyuki, Kazuto Akagi, Yoshihide Yoshimoto, Jun Yamauchi

    Journal of Physics and Chemistry of Solids　65　(2-3)　119-122　2004/02

    DOI： 10.1016/j.jpcs.2003.10.004 　

    ISSN： 0022-3697

  56. Indication of flat-band magnetism in theoretically designed nanographite with modified zigzag edges

    Kusakabe, K., Maruyama, M., Tsuneyuki, S., Akagi, K., Yoshimoto, Y., Yamauchi, J.

    Journal of Magnetism and Magnetic Materials　272-276　(SUPPL. 1)　2004

    DOI： 10.1016/j.jmmm.2003.12.1350 　

    ISSN： 0304-8853

  57. Unsaturated cyclic-hydrocarbon molecules on a Si(0 0 1) surface: A first-principles approach Peer-reviewed

    Kazuto Akagi, Shinji Tsuneyuki

    Surface Science　493　(1-3)　131-137　2001/11/01

    DOI： 10.1016/S0039-6028(01)01200-6 　

    ISSN： 0039-6028

  58. Reaction mechanism and adsorbed states of cyclohexene on Si(100)(2x1) Peer-reviewed

    J Yoshinobu, Y Yamashita, F Yasui, K Mukai, K Akagi, S Tsuneyuki, K Hamaguchi, S Machida, M Nagao, T Sato, M Iwatsuki

    JOURNAL OF ELECTRON SPECTROSCOPY AND RELATED PHENOMENA　114　383-387　2001/03

    ISSN： 0368-2048

  59. Theoretical study of the hydrogen relay dissociation of water molecules on Si(001) surfaces Peer-reviewed

    K. Akagi, M. Tsukada

    Surface Science　438　(1-3)　9-17　1999/09/10

    Publisher: Elsevier Science B.V.

    DOI： 10.1016/S0039-6028(99)00538-5 　

    ISSN： 0039-6028

  60. Interaction of H2O clusters with hydrogen-terminated and clean Si(011) surfaces Peer-reviewed

    Kazuto Akagi, Masaru Tsukada

    Thin Solid Films　343-344　(1-2)　397-400　1999

    Publisher: Elsevier

    DOI： 10.1016/S0040-6090(98)01686-1 　

    ISSN： 0040-6090

  61. Electronic properties of polygonal defects in graphitic carbon sheets Peer-reviewed

    Ryo Tamura, Kazuto Akagi, Masaru Tsukada, Satoshi Itoh, Sigeo Ihara

    Physical Review B - Condensed Matter and Materials Physics　56　(3)　1404-1411　1997

    DOI： 10.1103/PhysRevB.56.1404 　

    ISSN： 1550-235X 1098-0121

  62. Electronic states of nanostructures of curved graphitic carbon cages Peer-reviewed

    M. Tsukada, K. Akagi, R. Tamura, S. Ihara

    Surface Review and Letters　3　(1)　835-842　1996

    Publisher: World Scientific Publishing Co. Pte Ltd

    DOI： 10.1142/S0218625X96001509 　

    ISSN： 0218-625X

  63. Electronic structure of helically coiled carbon nanotubes: Relation between the phason lines and energy band features Peer-reviewed

    Kazuto Akagi, Ryo Tamura, Masaru Tsukada, Satoshi Itoh, Sigeo Ihara

    Physical Review B - Condensed Matter and Materials Physics　53　(4)　2114-2120　1996

    DOI： 10.1103/PhysRevB.53.2114 　

    ISSN： 1550-235X 1098-0121

  64. Structure of polygonal defects in graphitic carbon sheets Peer-reviewed

    Sigeo Ihara, Satoshi Itoh, Kazuto Akagi, Ryo Tamura, Masaru Tsukada

    Physical Review B - Condensed Matter and Materials Physics　54　(20)　14713-14719　1996

    DOI： 10.1103/PhysRevB.54.14713 　

    ISSN： 1550-235X 1098-0121

  65. Electronic structure of helically coiled cage of graphitic carbon Peer-reviewed

    Kazuto Akagi, Ryo Tamura, Masaru Tsukada, Satoshi Itoh, Sigeo Ihara

    Physical Review Letters　74　(12)　2307-2310　1995

    DOI： 10.1103/PhysRevLett.74.2307 　

    ISSN： 0031-9007

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Misc. 17

  1. トポロジカルデータ解析による複雑な顕微画像からの特徴抽出

    赤木 和人

    ふぇらむ (日本鉄鋼協会会報)　26　(3)　126-133　2021/03

  2. X-ray fluorescence holography for soft matter

    Artoni Kevin R. Ang, Ayana Sato-Tomita, Naoya Shibayama, Yasufumi Umena, Naohisa Happo, Riho Marumi, Koji Kimura, Tomohiro Matsushita, Kazuto Akagi, Takahiko Sasaki, Yuji C. Sasaki, Kouichi Hayashi

    Japanese Journal of Applied Physics　59　(1)　2020/01/01

    DOI： 10.7567/1347-4065/ab5d55 　

    ISSN： 0021-4922

    eISSN： 1347-4065

  3. パーシステントホモロジーと材料構造解析

    平岡 裕章, 大林 一平, 赤木 和人

    人工知能　34　(3)　330-338　2019/03

    DOI： 10.11517/jjsai.34.3_330 　

  4. ストロンチウム吸着特性を有するチタン酸塩ナノワイヤーの作製と評価

    齋藤哲平, 赤木和人, 中山幸仁, 阿尻雅文, 浅尾直樹, 浅尾直樹

    日本化学会春季年会講演予稿集(CD-ROM)　99th　2019

  5. 脱合金酸化法によるチタン酸塩ナノワイヤーの作製とストロンチウム吸着性能評価

    齋藤哲平, 赤木和人, 中山幸仁, 阿尻雅文, 浅尾直樹, 浅尾直樹

    日本原子力学会春の年会予稿集(CD-ROM)　2018　2018

  6. 8aAS-9 Low-coverage bottom-up graphene-nanoribbon fabrication

    Han Patrick, Akagi Kazuto, Canova Filippo Federici, Mutoh Hirotaka, Shiraki Susumu, Iwaya Katsuya, Weiss Paul S., Asao Naoki, Hitosugi Taro

    Meeting abstracts of the Physical Society of Japan　69　(2)　646-646　2014/08/22

    Publisher: The Physical Society of Japan (JPS)

    ISSN： 1342-8349

  7. 炭化水素で化学修飾したSi(100)表面におけるF4-TCNQの電子状態と配向

    向井孝三, 亀島一輝, 村瀬加内江, 小板谷貴典, 清水皇, 吉本真也, 赤木和人, 吉信淳

    PFシンポジウム要旨集　28th　2011

  8. Cycloaddition reaction on Si surfaces

    46　(7)　348-365　2008/07

    Publisher: 広信社

    ISSN： 0367-648X

  9. 23aXA-9 Depth dependence and that origin of electronic states at SiON/SiC(0001) surface

    Ando Yasunobu, Fujiwara Hiroyasu, Akagi Kazuto, Tsuneyuki Shinji, Shirasawa Tetsuroh, Tochihara Hiroshi

    Meeting Abstracts of the Physical Society of Japan　63　(0)　848-848　2008

    Publisher: The Physical Society of Japan

    ISSN： 1342-8349

  10. 21aRG-2 First-principles calculation of three-dimensionally polymerized fulluerene

    Kosugi Taichi, Akagi Kazuto, Tsuneyuki Shinji

    Meeting Abstracts of the Physical Society of Japan　62.1.4　858　2007

    Publisher: The Physical Society of Japan

    DOI： 10.11316/jpsgaiyo.62.1.4.0_858_1 　

    eISSN： 2189-0803

  11. Dynamics and Electronic States: A Water Reaction Elucidated from Surface Reactions: The Role of Proton Transport

    加藤浩之, 赤木和人

    固体物理　41　(11)　2006

    ISSN： 0454-4544

  12. 15aPS-29 Stability of excess Si defects near SiO_2/Si(100) interfaces

    Kageshima H., Uematsu M., Akagi K., Tsuneyuki S., Akiyama T., Shiraishi K.

    Meeting Abstracts of the Physical Society of Japan　59　(0)　830-830　2004

    Publisher: The Physical Society of Japan

    DOI： 10.11316/jpsgaiyo.59.2.4.0_830_1 　

    ISSN： 1342-8349

  13. 15pXE-1 Site-specific observation of the electronic structure at SiO_2/Si interface

    Yamashita Y, Yamamoto S, Mukai K, Yoshinobu J, Harada Y, Takata Y, Shin S, Akagi K, Tsuneyuki S

    Meeting Abstracts of the Physical Society of Japan　59　(0)　843-843　2004

    Publisher: The Physical Society of Japan (JPS)

    ISSN： 1342-8349

  14. Stability of excess Si defects near SiO_2/Si(100) interfaces

    Kageshima H., Akiyama T., Akagi K., Uematsu M., Shiraishi K., Tsuneyuki S.

    Meeting Abstracts of the Physical Society of Japan　58　(0)　857-857　2003

    Publisher: The Physical Society of Japan

    DOI： 10.11316/jpsgaiyo.58.2.4.0_857_1 　

    ISSN： 1342-8349

  15. Possibility of surface design: unsaturated cyclic-hydrocarbon on Si(001) substrate

    Akagi K., Tsuneyuki S., Yoshinobu J.

    Meeting abstracts of the Physical Society of Japan　55　(2)　751-751　2000/09/10

    Publisher: The Physical Society of Japan (JPS)

    ISSN： 1342-8349

  16. Towards the Fabrication of Atomically Controlled Novel Organic Films/Si Hybrid Structures

    YAMASHITA Y, MUKAI K, AKAGI K, TSUNEYUKI S, YOSHINOBU J

    Technical report of IEICE. OME　100　(245)　69-73　2000/07/21

    Publisher: The Institute of Electronics, Information and Communication Engineers

    ISSN： 0913-5685

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    In order to fabricate atomically controlled organic materials on Si surfaces, the adsorbed states of 1, 4-cyclohexadiene and cyclohexene on Si(100)(2x1) were investigated. For 1, 4-cyclohexadiene, the 1, 4-cyclohexadiene molecules are aligned on the dimers row of Si(100)(2x1), remaining one of the two πbonds. In the case of cyclohexene, on the other hand, two adsorbed states were observed by STM. Using density functional calculations, these states are attributed to the chair and boat structures of conformational isomers for cyclohexene molecules on Si(100)(2x1). This system may introduce the possibility of single molecular devices, using the conversion of the two isomers reversibly.

  17. Proton Relay Dissociation of Water Molecules on a Si(001) Surface

    AKAGI Kazuto, TSUKADA Masaru

    Journal of the Surface Science Society of Japan　21　(1)　39-48　2000

    Publisher: 日本表面科学会

    DOI： 10.1380/jsssj.21.39 　

    ISSN： 0388-5321 1881-4743

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Books and Other Publications 2

  1. マテリアルズインフォマティクス = Materials informatics

    吉田, 亮, 伊藤, 聡, 劉, 暢, Wu, Stephen, 野口, 瑶, 山田, 寛尚, 赤木, 和人, 大林, 一平, 山下, 智樹

    共立出版　2022/08

    ISBN: 9784320072022

  2. マテリアルズ・インフォマティクスQ&A集 : 解析実務と応用事例

    情報機構　2020/12

    ISBN: 9784865022049

Presentations 17

  1. Quantitative assessment of fiber alignment in CFRP using Persistent Homology

    Xichan Gao, Kazuto Akagi, Daiki Kido, Mayrene Uy, Masao Kimura

    The 72nd JSAP Spring Meeting 2025　2025/03/16

  2. 固体電解質中のイオンダイナミクスのトポロジカルデータ解析

    赤木 和人

    第72回応用物理学会春季学術講演会　2025/03/16

  3. 幾何学的に特徴付けられた共晶Mo-TiC合金のミクロ組織と機械的性質の関係

    日本金属学会 2025年春期 第176回講演大会　2025/03/08

  4. Detecting and quantifying structural information in X-CT images of CFRP using topological data analysis

    Xichan Gao, Kazuto Akagi, Daiki Kido, Mayrene Uy, Masao Kimura

    2024/12/21

  5. トポロジカルデータ解析を用いてミクロ構造とマクロ物性をつなぐ Invited

    赤木 和人

    第75回白石記念講座「データ駆動型材料開発の最前線とその適用例」　2024/11/21

  6. A Regression Model of CO2 Uptake for Metal–Organic Frameworks based on Structural Descriptors International-presentation

    Kazuto Akagi, Hisashi Naito, Takafumi Saikawa, Motoko Kotani, Hirofumi Yoshikawa

    the 10th International Symposium on Surface Science　2024/10/23

  7. 機械学習を使ったMoSiBTiC合金のミクロ組織と硬度の相関の評価

    弦木 健太郎, 赤木 和人, 井田 駿太郎, 吉見 享祐

    日本金属学会 2024年秋期 第175回講演大会　2024/09/18

  8. 組織画像の構造的特徴に基づく鉄鋼材料の引張強度の予測と理解 Invited

    赤木 和人, 大林 一平, 平岡 裕章, 西浦 廉政

    日本金属学会 2024年秋期 第175回講演大会　2024/09/18

  9. トポロジカルデータ解析を用いた金属組織画像の定量化と力学特性予測 Invited

    赤木 和人

    令和5年度 軽金属学会東北支部講演会　2024/03/29

  10. Detecting and Quantifying Structural Information in X-CT Images Using Topological Data Analysis

    Xichan Gao, Kazuto Akagi, Daiki Kido, Masao Kimura

    The 71st JSAP Spring Meeting　2024/03/24

  11. Finding “Trigger Sites” of Reactions Among Heterogeneous Materials from X-ray Microscopic Big Data Using Persistent Homology International-presentation

    Masao Kimura, Ippei Obayashi, Daiki Kido, Yasuhiro Niwa, Xichan Gao, Kazuto Akagi

    2024 TMS Annual Meeting & Exhibition　2024/03/04

  12. Finding “trigger sites” of reactions among the heterogeneity of materials by using X-ray microscopy and persistent homology analysis International-presentation

    Masao Kimura, Ippei Obayashi, Daiki Kido, Yasuhiro Niwa, Toshiki Watanabe, Yasuo Takeichi, Xichan Gao, Kazuto Akagi, Yasuaki Hiraoka

    Materials Research Meeting 2023 (MRM2023)　2023/12/15

  13. Identification of Structural Information from X-ray CT Images Based on Topological Data Analysis International-presentation

    Xichan Gao, Kazuto Akagi, Daiki Kido, Masao Kimura

    Materials Research Meeting 2023 (MRM2023)　2023/12/15

  14. Topological Data Analysis Based on Persistent Homology for the Superionic Conductors International-presentation

    Ryuhei Sato, Kazuto Akagi, Shigeyuki Takagi, Kartik Sau, Kazuaki Kisu, Hao Li, Shinichi Orimo

    Materials Research Meeting 2023 (MRM2023)　2023/12/14

  15. Topological Data Analysis of Complex Metal Structure in SEM Images and Construction of Regression Models for Mechanical Properties International-presentation

    Kazuto Akagi, Yasumasa Nishiura

    Materials Research Meeting 2023 (MRM2023)　2023/12/14

  16. Analysis of Massive Molecular Dynamics Simulation Based on Topological Data Analysis

    Xichan Gao, Kazuto Akagi

    The 70th JSAP Spring Meeting 2023　2023/03/18

  17. シミュレーションデータのミクロな「形」とマクロなイオン挙動をつなぐ Invited

    赤木 和人

    第２回計算イオニクス研究会　2023/03/03

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Industrial Property Rights 1

  1. 複合材料の検査装置及び方法並びに複合材料の検査プログラム及びそのプ ログラムを記録したコンピュータ読み取り可能な記憶媒体

    木村 正雄, 城戸 大貴, ガオ シーチャン, 赤木 和人

    Property Type: Patent

Research Projects 11

  1. データ記述科学を用いた材料解析とそのイノベーション展開

    木村 正雄, 武市 泰男, 稲田 康宏, 赤木 和人, 岡本 敦

    Offer Organization: 日本学術振興会

    System: 科学研究費助成事業

    Category: 学術変革領域研究(A)

    Institution: 大学共同利用機関法人高エネルギー加速器研究機構

    2022/06/16 - 2027/03/31

  2. Local atomic structures of amorphous electrode materials and charge-discharge mechanism

    Hirata Akihiko

    Offer Organization: Japan Society for the Promotion of Science

    System: Grants-in-Aid for Scientific Research

    Category: Grant-in-Aid for Scientific Research (A)

    2017/04/01 - 2020/03/31

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    In this work, we developed some novel analytical techniques for amorphous materials based on our previous techniques and applied them to the structure analyses on amorphous electrodes of Li-ion batteries. As a result, it has become possible to obtain significant structural information which have not been obtained yet. Moreover, local structural information during charge-discharge process was also obtained by analyzing amorphous materials after the charge-discharge treatments. We will further obtain more information about the microscopic structures to understand the charge-discharge mechanism of Li-ion batteries.

  3. First-principles Theoretical Elucidation and Design of Active Sites in Functional Materials

    Morikawa Yoshitada, INAGAKI Kouji, ONO Tomoya, KIZAKI Hidetoshi, HAMAMOTO Yuji, MIYAZAKI Tsuyoshi

    Offer Organization: Japan Society for the Promotion of Science

    System: Grants-in-Aid for Scientific Research

    Category: Grant-in-Aid for Scientific Research on Innovative Areas (Research in a proposed research area)

    Institution: Osaka University

    2014/07/10 - 2019/03/31

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    In this research project, we have developed first-principles electronic structure calculation program code that can accurately and efficiently calculate local structures of materials at the atomic level, and by using it, we have clarified the relation between local atomic geometries in materials and physical and chemical properties of those materials. Local atomic geometries of materials and the relation to their functions are quite often difficult to elucidate experimentally, and therefore, roles played by our first-principles simulations are very important in this field. Specifically, we have succeeded in clarifying the atomic structures and electronic and chemical properties of highly doped As in Si semiconductor devices, Pt single-atom catalysts supported on graphene nanoribbon in fuel cell electrodes, Mn doped in ZnSnAs2 for diluted magnetic semiconductors, Rh doped SrTiO3 for photocatalysts, X-ray induced damage in BEDT-TTF organic materials.

  4. Study of 3D local structures around magnetic elements in room temperature ferromagnetic semiconductors

    Hayashi Koichi, Fukumura Tomoteru, Uchitomi Naotaka, Akagi Kazuto

    Offer Organization: Japan Society for the Promotion of Science

    System: Grants-in-Aid for Scientific Research

    Category: Grant-in-Aid for Scientific Research (B)

    2013/04/01 - 2017/03/31

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    To understand local structures around magnetic elements, we measured X-ray fluorescence holograms of Co:TiO2 thin film, Mn:ZnSnAs2 thin film and GeMnTe thin film. In Co:TiO2 thin film, we discovered suboxide clusters around Co. The crystal structure of ZnSnAs2 thin film was sphalerite-type, and the As sublattice was largely distorted. Moreover, the local structure around Ge in GeMnTe thin film, reflecting rhombohedral GeTe structure, had lower symmetry than that around Mn.

  5. Studies on Structure Sampling and Non-Equilibrium Dynamics Using Ab-Initio Molecular Dynamics Methods

    TSUNEYUKI Shinji, OTANI Minoru, YOSHIMOTO Yoshihide, YAMAUCHI Jun, NAKAYAMA Takashi, SUGINO Osamu, MORIKAWA Yoshitada, AKAGI Kazuto, TATEYAMA Yoshitaka, SUWA Yuji, GOHDA Yoshihiro

    Offer Organization: Japan Society for the Promotion of Science

    System: Grants-in-Aid for Scientific Research

    Category: Grant-in-Aid for Scientific Research on Innovative Areas (Research in a proposed research area)

    Institution: The University of Tokyo

    2010/04/01 - 2015/03/31

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    This project is mainly dedicated to first-principles study on thermal physics and non-equilibrium dynamics in condensed matter. For long-time/large-scale simulation needed for the purpose, we developed "xTAPP", a highly parallelized and multi-functional program package for first-principles molecular dynamics simulation. We also developed an efficient scheme of modeling anharmonic interaction between atoms from first principles for accurate calculation of lattice thermal conductivity. For the simulation of electrochemical reaction, we extended the effective screening medium method previously proposed by one of our members, with which simulations of electrochemical reaction under arbitrary and constant bias voltage was realized. "xTAPP" and the program package "ALAMODE" for lattice thermal conductivity were published as open source codes.

  6. Elucidation of the behavior of hydrogen and hydroxyl ions based on the hydrogen-bond network analysis

    AKAGI Kazuto

    Offer Organization: Japan Society for the Promotion of Science

    System: Grants-in-Aid for Scientific Research

    Category: Grant-in-Aid for Challenging Exploratory Research

    Institution: Tohoku University

    2012/04/01 - 2014/03/31

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    Elucidation of the rule which determines the behavior or spatial distribution of hydronium and hydroxyl ions in aqueous solutions will lead to the way of understanding or controlling of various catalytic reactions. In this project, systematic analyses of the hydrogen-bond network, which consists of weak bonds among water molecules, were done focusing on the "ring structures" included in it, and two important findings were obtained as follows: (1) Liquid water involves the microscopic inhomogeneity caused by these "ring structures", and (2) Hydronium and hydroxyl ions feel repulsive interaction from a certain kind of "ring structure". These concepts are based on the results from computer simulations, but it was also implied that they are relatively independent from the accuracy of how to model the atoms and molecules.

  7. Theoretical study on property of aqueous solution and electrochemical process at nano-space

    TSUKADA Masaru, AKAGI Kazuto, TAMURA Hiroyuki, HAMADA Ikutaro, MASAGO Akira, ARAIDAI Masaaki

    Offer Organization: Japan Society for the Promotion of Science

    System: Grants-in-Aid for Scientific Research

    Category: Grant-in-Aid for Scientific Research (A)

    Institution: Tohoku University

    2009 - 2012

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    Structure and dynamics of aqueous electrolyte solution at the solid-liquid interface was investigated based on various molecular simulation methods. Microscopic understanding on typical space and time scale of interfacial systems, behavior of ionic species in a hydrogen-bond network and the origin of electric double layer structure were given. Hydrogen evolution processes at an “acid solution / Pt electrode" interface were quantitatively evaluated taking account of the effect of electrode potential. Theoretical frameworks to treat the electron transfer process across the interface induced by photo excitation or applied electric field were developed.

  8. Theory of nano-link molecules

    TSUKADA Masaru, KOBAYASHI Nobuhiko, MORIKAWA Yoshitada, TSUNEYUKI Shinji, MAKOSHI Kenji, UEBA Hiromu, AKAGI Kazuto, AIZAWA Hideaki

    Offer Organization: Japan Society for the Promotion of Science

    System: Grants-in-Aid for Scientific Research

    Category: Grant-in-Aid for Scientific Research on Priority Areas

    Institution: Waseda University

    2005 - 2009

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    Theoretical approaches of molecular transport were developed based on the non-equilibrium green's function method using the first-principles density functional method, and applied various important organic molecular bridges forming nano-links with electrodes. By these studies, fundamental mechanism and properties of the electron transport of molecules were elucidated. Important features of inelastic electron tunneling involving the excitation of molecular vibration have been clarified and bases of inelastic tunneling spectroscopy have been established. The method treating the interaction between the electron motion and molecular vibration was developed, and with it the issues of heat generation and thermal conduction were researched. The mechanism of the transition from the coherent transport to the dissipative transport has been also clarified.

  9. Electronic properties of single and arranged organic molecules on semiconductor surfaces

    YOSHINOBU Jun, YAMASHITA Yoshiyuki, TSUNEYUKI Shinji, AKAGI Kazuto

    Offer Organization: Japan Society for the Promotion of Science

    System: Grants-in-Aid for Scientific Research

    Category: Grant-in-Aid for Scientific Research (B)

    Institution: The University of Tokyo

    2004 - 2005

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    We investigated adsorbed states and electronic structures of organic molecules on the Si(100) surface experimentally and theoretically. Obtained results are summarized as follows. (1)We found out the regioselective cycloaddition reaction between asymmetric alkene molecules and the asymmetric dimer on Si(100)c(4x2) using low temperature STM. The first principles calculations have elucidated the reaction mechanism. (2)Photo induced reaction and desorption were investigated for the π-complex type weakly adsorbed ethylene on Si(100)c(4x2). (3)Adsorbed states of 1,4-cyclohexadiene were investigated as a function of adsorption temperature. Three different adsorbed states were found out using STM. The STS measurements of room-temperature adsorbed species (probably a table type species) were performed. (4)The electronic states of interface at SiO_2/Si(111) were directly probed by means of soft-X ray emission spectroscopy using SPring8. The site-specific electronic states are elucidated for the first time. (5)In the framework of the first principles calculation, the electronic states of organic molecules on Si(100) under electric bias were investigated. Energy shifts of molecular orbitals depend on the height and the strength of electric field. (6)We have constructed an apparatus including a fine electron gun which can be used for electron induced surface reaction in order to fabricate sub μm artificial structures. We demonstrated the electron-induced iron deposition from Fe(CO_)5 multilayer on Si(100).

  10. 2次元場に固定された配向分子の反応

    吉信 淳, 赤木 和人, 常行 真司, 山下 良之

    Offer Organization: 日本学術振興会

    System: 科学研究費助成事業

    Category: 特定領域研究

    Institution: 東京大学

    2000 - 2002

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    1.Si(100)表面の非対称ダイマーの反応性について Si(100)(2x1)の非対称ダイマーは,原子間で電荷移動が生じ,上部ダイマー原子はネガティブに,下部ダイマー原子はポジティブにチャージしているので,それぞれルイス塩基的・ルイス酸的にふるまうことが期待される.サイト選択的反応を調べるために,CO,BF_3,ピリジン,トリメチルアミン(TMA)などを導入し,高分解能内殻光電子分光,高分解能電子エネルギー損失分光,走査型トンネル顕微鏡などを用いて,表面Si原子の化学状態や分子種の吸着状態を調べた. 2.Rh(111)表面における水の吸着と氷の成長 25KのRh(111)表面における水分子の吸着過程と,アモルファス氷への成長,加熱による結晶性氷への変化を,赤外反射吸収分光(IRAS)で詳細に調べた.単分子層以下では,水分子はRh(111)表面で,モノマーからダイマー,テトラマーなどへクラスターし,水素結合ネットワークを形成し,その後アモルファス氷が3次元的に形成される過程を明らかにした. 3.電子線誘起による氷中での分子進化 CO分子を低温氷薄膜中に閉じこめ電子線を照射したところ,CO2,ホルムアルデヒド,メタノールなどの分子が生成することを見いだした. 4.理論班では、低温の氷中での化学反応は水分子の回転の抑制された条件で進む点に注目してプロトンの移動が本質的な働きをすることを予想し、特定の条件の下で氷中のCO分子が水分子と酸化還元反応を起こして一連のC1化合物を生成する機構を題材として、まず基底状態における反応経路を探索した。

  11. 「水溶液/半導体」界面における水分子の協調的な振舞いを利用した反応制御

    赤木 和人

    Offer Organization: 日本学術振興会

    System: 科学研究費助成事業

    Category: 奨励研究(A)

    Institution: 東京大学

    2000 - 2001

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    本年度も引き続き、密度汎関数法に基づく第一原理計算を用いて複数の水分子が表面や異種分子と相互作用したときの協調的なはたらきを調べた。その結果、水素結合をした水分子同士の「酸素-酸素間距離の短縮」と、複数の水分子が次々に水素を伝達する「プロトンリレー型反応」との間に密接な関係があり、このタイプのモデルが固体表面における水分子の反応のみならず、水溶液の溶質分子の酸化還元といった反応においても普遍的かつ重要な役割を果たしていることを示す知見が得られた。 その特徴は、それが氷の高圧相や水素を含むアルミニウム酸化物の高圧相などに見られる物理的な圧縮の結果得られた系全体に広がるものではなく、ダングリングボンドを有する化学的に活性な表面や親水性の分子が水のフェルミ準位近傍の分子軌道と相互作用するという化学的な要因で生じた局所的なものであるということである。そしてこのような水素結合の変性は、静的な状態では、溶質分子や固体表面の分子軌道の張り出し応じて、複数の水分子をつなぐ1つあるいは複数の環としてあらわれる。 この研究の目指すところは「反応制御」であるので、この水素結合の変性を意図した領域に発生させることがテーマのひとつであった。しかし実際に系の計算を行なってみると、プロトンリレーに関与する水分子の数は4分子に達することもしばしばであり、もともと反応性のある表面・分子で反応のON-OFFを制御するのは困難であった。一方、水との反応性が乏しいと思われている疎水性の分子であっても、「水素結合の変性領域」と接触させることで比較的容易に反応を起こす可能性が出てきている。 これらについてまとめた「Si(001)表面/バルクの水系のダイナミクス」および「水クラスタ中のギ酸の分解反応」については論文投稿の準備中である。

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