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筑波大学 数理物質系
物質工学域 近藤研究室


Seminar and invited talk

Invited talk
Materials Science Seminar
 Date:  17th Dec. 2019 (PM 15:15-16:15)
 Location:  3B213
 Title: Geo‐inspirationto extend the library of functional inorganic nanoparticles
 Speaker: Dr. David Portehault
 Laboratoire de Chimie de la Matiere Condensee de Paris (LCMCP), Researcher of CNRS

Invited talk
Materials Science Seminar
 Date:  16th Jan. 2019 (AM 10:30-11:30)
 Location:  3B213
 Title: Physical Chemistry with Single Molecules- Hydrogen-Transfer
        Dynamics Studied by Scanning Probe Microscopy

 Speaker: Dr. Takashi Kumagai
 Group leader, Department of Physical Chemistry, Fritz-Haber Institute
  H-atom transfer and H-bond rearrangement are involved in many important physical,
  chemical, and biological processes such as proton conductor, acid?base reactions,
  and DNA [1]. However, an accurate and quantitative description of H-atom/bonding
  dynamics remains a very challenging topic and nuclear quantum effects (NQEs) and
  anharmonicity of the potential energy surface are outstanding problems in the field.
  In order to examine such dynamics, it is necessary to investigate model systems at
  the single-molecule level because NQEs and anharmonic nature are quite susceptive
  to a local environment of individual molecules and hidden by inhomogeneities of
  bulk samples. Low-temperature SPM has provided a new opportunity to study
  hydrogen-atom/bonding dynamics [2]. Single-molecule tautomerization serves as a
  fascinating model and I will discuss hydrogen-transfer reactions occurring through
  various external stimuli as well as quantum tunneling [3].
  [1] Hydrogen-transfer reaction. J. T. Hynes, J. P. Klinman, H.-H. Limbach, R. L.
    Schowen, Weley-VCH, 2007.
  [2] TK, Prog. Surf. Sci. 90, 239 (2015).
  [3] TK et al. Phys. Rev. Lett. 111, 246101 (2013).; TK et al. Nature Chem. 6, 41 (2014).;
    J. Ladenthin et al. ACS Nano 9, 7287 (2015).; H. Bockmann et al. Nano Lett. 16, 1034
     (2016).; J. Ladenthin et al. Nature Chem. 8, 935 (2016).; M. Koch et al. J. Am. Chem.
    Soc. 139, 12681 (2017).; TK, J. Chem. Phys. 148, 102330 (2018):; H. Bockmann et al.
    Nano Lett. 18, 152 (2018).

(Seminar and invited talk up to 2017)


Invited talk
 日時: 2016年 11月24日(木)14時30分開始予定(60分程度)
 場所: 3B213プレゼンテーションルーム
 タイトル:Eley-Rideal reactions of hot atoms and molecules at surfaces
 講師: Professor Dr Aart W. Kleijn(Director, Center of Interface Dynamics
 for Sustainability, Institute of Materials, CAEP)
  Most chemical reactions proceed along the Langmuir-Hinshelwood (LH) route:
  reactants adsorb at a surface and possibly dissociate, the adsorbates diffuse
  over the surface, find reaction partners, and form a product molecule that
  subsequently desorbs. Because making and breaking of bonds is more facile at
  surfaces than in the gas or liquid phase, heterogeneous catalysis is applied
  a lot in (bulk) chemistry. It decreases activation barriers and steers the
  reaction in the desired direction.
  The mechanism of incident radicals, for which no chemical bond needs to be
  broken, can proceed in a different way. Often these reactions are exothermic
  and can act promptly. That the mechanism is different was already recognized
  by Eley and Rideal (ER) around 1940.
  Such reactions are rare and recently have been studied extensively for hydrogen
   atoms. For non-hydrogenic, ‘heavy’ atoms they were considered unlikely.
  Recently at the FOM Institute DIFFER we have identified such reactions for
  hyperthermal nitrogen atoms reacting with adsorbed O or N atoms on Ag and Ru.
  The reaction cross sections are surprisingly large, an up to now not fully
  understood effect. The mechanism of such ER reactions will be discussed in this
  One way of turning (LH) reactions into ER reactions could be by specific excitation
  of the internal degrees of freedom of molecules. Vibrational excitation of CH4
  leads to much larger dissociative sticking coefficients. We have started a project
  to increase the reactivity of CO2 by plasma activation. Both in the
  gas phase and for reactions at a catalyst distinct effects of the plasma activation
  can be observed. In this presentations first results of plasma catalysis of
  CO2 will be shown.

Invited talk
 日時: 2016年 11月16日(水)13時00分開始予定(60分程度)
 場所: 3B213プレゼンテーションルーム
 講師: (株)豊田中央研究所 中野秀之 主席研究員
  本講演では、Zintl silicideの一つであるCaSi2から誘導
  R.Yaokawa, T. Ohsuna, T. Morishita, Y. Hayasaka,
  M. J. S. Spencer & H.i Nakano, Nature Communications 7, 10657 (2016)

Invited talk
 日時: 2015年 3月10日(火)17時00分開始予定(60分程度)
 場所: 総合研究棟B611
 講師: 東京工業大学 宮内 雅浩 准教授

Invited talk
 日時: 2014年 12月8日(月)17時00分開始予定(60分程度)
 場所: 3B213プレゼンテーションルーム
 タイトル:Controlling a chemical reaction on a surface: applications for
        scanning probe microscopy.

 講師: Prof. Sylvain Clair (CNRS, Aix-Marseille University, Marseille, France)
  Two-dimensional (2D) polymers are expected to have a great impact on many
  fundamental and applied aspects of science. Some recent demonstrations of
  covalent polymerization performed directly at surfaces have opened promising
  perspectives.[1] The polymer formation is usually obtained by deposition
  of the molecular precursors on the surface followed by thermal activation
  of the polymerization reaction. In particular, boronic acids can undergo a
  self-condensation (dehydration) reaction to create rigid boroxine rings and
  a planar polymer sheet. By using 1,4-benzenediboronic acid (BDBA) evaporated
  onto a well-defined metal surface, extended nanoporous 2D networks could grow.
  I will present recent scanning tunneling microscopy (STM) results in ultrahigh
  vacuum (UHV) reflecting various efforts to control the growth process of these
  two-dimensional covalent organic frameworks (influence of the deposition
  parameters, local activation of the reaction, coupling with an Ullmann reaction,
   In a second part I will show how the probe of an atomic force microscopy (AFM)
  can locally and selectively initiate a chemical reaction. Scanning probe
  lithography (SPL) is a highly promising tool for the creation of specific
  nanosized patterns on a surface with high spatial resolution. We reported a novel
  approach to chemically selective lithography using AFM probe with immobilized
  homogeneous catalyst, potentially opening an access to a diversity of nanoscale
  transformations of the surface-bound functional groups.[3] This new concept was
  proven for local epoxidation of alkene-terminated self-assembled monolayer on
  silicon using H2O2 as an oxidant and a catalytic silicon
  AFM tip charged with manganese complexes with 1,3,7-triaza-cyclononane type ligand.
  By varying the reaction parameters (scanning speed, force applied), important
  insights into the reaction mechanism could be obtained.
  [1] J. Bjork, F. Hanke, Chemistry-a European Journal 20, 928 (2014)
  [2] S. Clair, M. Abel, L. Porte, Chemical Communications 50, 9627 (2014)
  [3] D. Valyaev et al., Chemical Science 4, 2815 (2013)

Invited talk
 日時: 2012年 12月18日(火)17時00分開始予定(60分程度)
 場所: 総合研究棟B108
 タイトル:Adsorption, clustering and reaction of H atoms on graphene surface defects.
 講師:Dr.Simone Casolo(Dept. Chemistry, University of Milan, Italy)
  Recent years have witnessed an ever growing interest in carbon based materials,
  especially after the experimental observation of graphene. In this context, adsorption
  of hydrogen atoms on graphene and nanoribbons can be used to tailor their electronic and
  magnetic properties, as already suggested for other“defects,” with the advantage of being
  easier to realize than, e.g. C vacancies. In addition, interaction of hydrogen atoms with
  graphitic compounds has been playing an important role in a number of fields as diverse as
  coatings for nuclear fusion reactors, hydrogen storage, and interstellar chemistry.
  Hydrogen atoms are known to chemisorb onto graphitic surfaces to form dimers, that can react
  forming H2 molecules. Here we review the mechanism of chemisorption and dimers
  formation in graphene bulk and edges, that is governed by the peculiar aromatic electronic
  structure. Then we show recent dynamical simulations of H2 recombination through
  the Eley-Rideal mechanism, with both accurate quantum wave packet calculations on model
  potential energy surfaces and ab initio molecular dynamics. We show that steering of the
  projectile atom gives an important contribution to the reaction at low collision energies
  and prevents dimers formation. At higher energies, on the other hand, the so-called ortho
  and para dimers form abundantly, in agreement with recent STM and molecular beams
  experiments. As well, we show preliminary calculations about the mechanism of H adsorption
  on single carbon vacancies and nanoribbon edges, stressing their possible applications in
  understanding carbon magnetism and catalytic activity.

Invited talk
 日時: 2012年 10月2日(火)10時10分開始(60分程度)
 場所: 総合研究棟B108
 タイトル:A day in the life of an adsorbate: new experimental approaches to dynamics
        on the nano-scale.

 講師:Prof. W. Allison(Surface Physics Group (SMF), Cavendish laboratory, University of Cambridge)
  Atoms and molecules move at surfaces on timescales lying typically
  between picoseconds and nano-seconds. The experimental challenge is to
  measure these fast processes on a sub-nanometre length scale. We have
  recently developed a spin-echo technique using atomic beams that combines
  surface sensitivity with the necessary spatial and temporal resolution [1].
  The talk will introduce and illustrate the technique through the
  behaviour of small molecular systems on well-characterised substrates.
  Rotation, as well as translation can be observed in unprecedented detail
  [2], together with evidence for inter-adsorbate interactions and
  frictional coupling to the substrate [3,4]. In favourable cases we learn
  not just about the adsorption ground-state but also gain information on
  the transition state for the motion.

  [1] AP Jardine et al, Science 304, 1790 (2004), Prog. Surf. Sci. 84, 323 (2009).
  [2] S. Paterson, et al. Phys. Rev. Lett. 106, 256101 (2011).
  [3] H. Hedgeland, et al. Phys. Rev. Lett. 106, 186101 (2011)
  [4] H. Hedgeland, et al. Nature Phys. 5, 561 (2009).

Invited talk
 日時: 2011年 6月24日(金)15時15分開始(1時間程度)
 場所: 総合研究棟B108
 講師:横浜市立大学大学院生命ナノシステム科学研究科 横山 崇 教授
  STM 観察やトンネル電子分光による直接観察によって明らかになった結果を報告

  [1] 日本物理学会誌(2011)
  [2] JCP(2001), JPC B(2006), JPC B(2008), JCP(2008)
  [3] PRL(2007), PRB(2010)
  [4] Nature(2001), JACS(2002), JCP(2004), APL(2006+2010), AdvMater(200
    7), JPC C(2008+2009)

Invited talk
講演者: Prof. Michael Trenary(Department of Chemistry, University of Illinois at Chicago)
日時:  2010年 5月18日(火)17:00〜
場所:  総合研究棟B 110
題目:  Identification of Surface Intermediates on Pt(111): Reconciling Single-Molecule
         Observations by STM with IR Spectra of Monolayers
  A major goal of research in heterogeneous catalysis is to determine the mechanisms
  by which chemical reactions take place on transition metal surfaces. In pursuit of
  this goal, surface spectroscopic methods are often used to identify stable molecular
  species that form in the course of surface chemical reactions. The technique of
  reflection absorption infrared spectroscopy (RAIRS) has the sensitivity and
  resolution to measure the vibrational spectra of a large variety of molecular species
  present on surfaces at submonolayer coverages, including novel intermediates that are
  structurally distinct from species that are stable in the gas phase. As each molecule
  has a unique vibrational spectrum, RAIRS can be used to definitively identify
  particular chemical species. On the other hand, the technique is not quantitative
  and therefore does not readily yield the coverages of various species that might
  coexist on a surface. In contrast, with low temperature scanning tunneling microscopy
  (LT-STM) individual atoms and molecules can be observed and their absolute coverages
  readily determined. The LT-STM, however, generally lacks chemical specificity.
  By combining RAIRS data obtained at the University of Illinois at Chicago with LT-STM
  images obtained at the Institute of Chemical and Physical Research in Wakoshi, Japan,
  of the same surface chemical systems, a great deal of new and unique information on
  surface intermediates can be obtained. This will be illustrated with several adsorbates
  and their reactions on the Pt(111) surface. The methyl isocyanide molecule (CH3NC)
  forms coordination complexes with a variety of transition metals and undergoes several
  characteristic reactions, such as protonation at the N atom. This latter reaction is
  readily revealed to occur on Pt(111) with RAIRS. With the LT-STM, individual molecules
  of CH3NC are observed to be transformed into a new form through reaction with hydrogen,
  and based on the RAIRS results, this new form is inferred to be methylaminocarbyne,
  CH3HNC. The LT-STM can be further used to manipulate individual CH3NC and CH3HNC
  molecules, and to remove an H atom from CH3HNC to form CH3NC, a reaction that does not
  occur thermally. A similar correlation of RAIRS and LT-STM results has been obtained for
  various C2Hx species that form through the adsorption and reaction of acetylene and
  ethylene on Pt(111). Some of the C2Hx species that have been identified and characterized
  in this way include vinyl (CHCH2), vinylidene (CCH2), ethylidyne (C2H3), and ethynyl (CCH).

Invited talk
講演者: Prof. Mischa Bonn(FOM-Institute for Atomic and Molecular Physics AMOLF)
日時:  2009年 2月6日(金)14:00〜
場所:  総合研究棟B 512
題目:  Structure and dynamics of interfacial water
  Interfacial water is of importance for a variety of disciplines including electrochemistry,
  (photo-) catalysis and biology. Water interfaces are characterized by the interruption of
  the bulk hydrogen bonded network, which gives interfacial water its unique properties
  (e.g. high surface tension). Using surface-specific Vibrational Sum-Frequency Generation
   (VSFG) Spectroscopy, we investigate the vibrational spectrum of the outermost monolayer
  of interfacial water molecules. The O-H stretch vibration ofinterfacial water provides a
  sensitive marker of the local environment of interfacial water molecules. In time-resolved
  measurements, the vibrational lifetime of hydrogen-bonded interfacial water is determined
  using a novel, surface-specific 4th-order VSFG spectroscopy. The O-H stretch vibration of
  interfacial water is resonantly excited with an intense, 100 fs infrared pulse; the
  vibrational relaxation dynamics are followed with femtosecond, time-resolved VSFG
  spectroscopy. Our results reveal that interfacial water is structurally more homogeneous
  than previously thought [1]. Furthermore, ultrafast exchange of vibrational energy can
  occur between water surface and bulk water [2], but the occurrence of ultrafast resonant
  vibrational energy transfer depends critically on the details of the water interface [3].
  Finally, we demonstrate a new type of two-dimensional surface spectroscopy that allows
  one to follow the structural evolution of interfacial molecular systems in real-time.[4]

  [1] M. Sovago, R. Campen, G. Wurpel, M. Muller, H. Bakker and M. Bonn, Phys. Rev. Lett.
   2008 100 173901
  [2] M. Smits, A. Ghosh, M. Sterrer, M. Muller and M. Bonn Phys. Rev. Lett. 2007 98 098302.
  [3] A. Ghosh, M. Smits, J. Bredenbeck and M. Bonn J. Am. Chem. Soc. 2007 129 9608.
  [4] J. Bredenbeck, A. Ghosh, M. Smits and M. Bonn J. Am. Chem. Soc. 2008 130 2152.

Invited talk
講演者: Prof. J. R. Manson(Department of Physics and Astronomy Clemson University)
日時:  2008年 2月18日(月)13:30〜14:30
場所:  総合研究棟B 512
題目:  Direct Scattering, Trapping and Desorption in Atom-Surface Collisions
  When gas atoms or molecules collide with clean and ordered surfaces, under many circumstances
  the energy-resolved scattering spectra exhibit two clearly distinct features, the first due
  to direct scattering and the second due to trapping in the physisorption well with subsequent
  desorption. James Clerk Maxwell is credited with being the first to describe this situation
  by invoking the simple assumption that when an impinging gas beam is scattered from a surface
  it can be divided into a part that reflects specularly with no energy transfer and another
  part that equilibrates or accommodates completely and then desorbs with an equilibrium
  distribution. In this talk a scattering theory is presented, using an iterative algorithm and
  classical mechanics for the collision process, that describes both direct scattering and
  trapping-desorption of the incident beam. The initially trapped particles can be followed
  as they continue to make further interactions with the surface until they are all eventually
  promoted back into the positive energy continuum and leave the surface region. Consequently,
  this theory allows a rigorous test of the Maxwell assumption and determines the conditions
  under which it is valid. The theory also gives quantitative explanations of recent
  experimental measurements [S. J. Sibener et al., J. Chem. Phys. 119, 13083 (2003)] which
  clearly exhibit both a direct scattering contribution and a trapping-desorption fraction
  in the energy-resolved spectra.

Invited talk
講演者: 山本恵彦 (Prof. Shigehiko Yamamoto) 産総研客員研究員(筑波大名誉教授)
日時:  2007年 12月4日 15時〜16時
場所:  総合研究棟B 302
題目:  金属・半導体界面における電子エネルギーアライメント
内容:  1.はじめに
     2.化学ポテンシャル(Energy Level Alignmentの駆動源)
     3.エネルギーレベルアライメント(Energy Level Alignment)
     4.電荷中性準位 (Charge Neutrality Level :CNL)
     6.Carrier Injection Barriers

Invited talk
講演者: Prof. Daniel Farias (Universidad Autonoma de Madrid)
日時:  2007年 1月5日(月) 13:40〜14:50
場所:  総合研究棟B 110
題目:  Probing reaction dynamics at metal surfaces with H2 diffraction
  Studies of elementary collision processes of H2 with metal surfaces can provide
  benchmark tests of theoretical methods that are increasingly used to aid the design of new
  heterogeneous catalysts. Molecular beam and associative desorption experiments have been
  carried out to understand the main factors that govern H2 dissociation at the
  surface. In addition, vibrationally inelastic and rotationally inelastic scattering
  experiments have provided useful information on how certain features of the potential
  energy surface (PES) control the experimental observations. A different point of view
  is provided by diffraction experiments. H2 diffraction from metal surfaces
  is more complex than He diffraction, since the PES is six-dimensional and the coupling
  with the dissociative adsorption channels comes into play. Thus, H2 diffraction
  is a verya promising technique to gauge the molecule-surface PES and dynamics. We have
  recently shown that this is possible by performing H2 diffraction experiments
  on reactive Pd(111) and non reactive NiAl(110) surfaces at 70-150 meV. By comparing with
  six-dimensional quantum dynamics and classical trajectory calculations we showed for the
  first time that accurate diffraction patterns can be obtained from state-of-the-art PES
  based on density functional theory . Once the PESs are validated, they can be used to
  study in detail the relationship between the trajectories followed by the H2
  molecules and the different channels involved in reactivity, like direct dissociation
  and dynamic trapping. Finally, I will address the problem of the validity of the Born-
  Oppenheimer approximation for molecule-metal surface reactions, which has been recently
  questioned due to the possibility of electron-hole pair excitations . We have performed
  experiments and six-dimensional quantum dynamics calculations on the scattering of
  molecular hydrogen from Pt(111), obtaining absolute diffraction probabilities. The
  comparison for in-plane and out-of-plane scattering, and results for dissociative
  chemisorption in the same system, show that for hydrogen-metal systems, reaction and
  diffractive scattering can be accurately described using the Born-Oppenheimer
  approximation .

  1 G. J. Kroes and M. F. Somers, J. Theor. Comput. Chem. 4, 493 (2005).
  2 D. Farias and K.H. Rieder, Rep. Prog. Phys. 61, 1575 (1998).
  3 D. Farias, C. Diaz, P. Riviere, H. F. Busnengo, P. Nieto, M. F. Somers,
   G. J.Kroes, A. Salin and F. Martin, Phys. Rev. Lett. 93, 246104 (2004).
  4 J. D. White, J. Chen, D. Matsiev, D. J. Auerbach, A. M. Wodtke, Nature 433, 503 (2005).
  5 P. Nieto, E. Pijper, D. Barredo, G. Laurent, R. A. Olsen, E. J. Baerends, G. J. Kroes,
   and D. Farias, Science 312, 86 (2006); A. M. Wodtke, ibid. 64; D. Clary, Nature Materials
   5, 345 (2006).