日本語 　　English 　　ホーム 　　メンバー 　　研究 　　論文 　　受賞 　　主催セミナー 　　ゼミ 　　How to join 　　アクセス 　　リンク 〒305-8573 茨城県つくば市天王台1-1-1 筑波大学 数理物質系 物質工学域 近藤研究室 見学希望、大学院進学希望の方など、気軽にご連絡下さい。 takahiro_at_ims.tsukuba.ac.jp

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 　　 　Abstract:PDF 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 　　 　Abstract： 　　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]. 　　 　　References 　　[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). 以下は表面触媒科学グループの過去の（中村・近藤研の）主催セミナー (Seminar and invited talk up to 2017) （これまでのセミナーより転載） Invited talk 　　セミナー 　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） 　　 　アブストラクト： 　　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 　　presentation. 　　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 　　セミナー 　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 　タイトル：劈開できないシリコンから二次元シリコン物質を創る技術 　講師： (株)豊田中央研究所 中野秀之 主席研究員 　　 　アブストラクト： 　　シリコンはダイヤモンド型構造をとるため劈開面が無い。 　　それ故、同族元素である黒鉛構造のカーボンのように 　　剥離法によって二次元シートを取り出すことは困難である。 　　本講演では、Zintl silicideの一つであるCaSi2から誘導 　　される層状シリコン化合物に着目し、これらを単層剥離して 　　得られる二次元シリコン物質群の合成と機能について紹介する。 　　 　　 　　Reference: 　　R.Yaokawa, T. Ohsuna, T. Morishita, Y. Hayasaka, 　　M. J. S. Spencer & H.i Nakano, Nature Communications 7, 10657 (2016) Invited talk 　　セミナー 　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 　タイトル：半導体光触媒による環境浄化とエネルギー製造 　講師： 東京工業大学　宮内　雅浩 准教授 　　 　アブストラクト： 　　半導体光触媒は抗菌・抗ウイルス等の環境浄化や水素生成等のエネルギー製 　　造技術として期待されている。本報告では、これまでの光触媒の研究開発の歴史 　　を述べた上、界面の光励起プロセスを利用した新規な可視光応答型光触媒の 　　開発について紹介する。更に、開発した光触媒のセルフクリーニング部材や 　　抗菌・抗ウイルス用途への応用と、空港、病院などの施設における実証試験 　　について報告する。 Invited talk 　　セミナー 　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） 　　 　アブストラクト： 　　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, 　　nanopatterning).[2] 　　 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. 　　 　　References: 　　[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 　　セミナー 　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） 　　 　アブストラクト： 　　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 　　物質科学セミナー 　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） 　　 　アブストラクト： 　　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 　　物質科学セミナー 　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 　タイトル：走査型トンネル顕微鏡を用いた表面吸着ナノサイズ分子の直接観察 　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 　　 　アブストラクト： 　　近年、有機EL素子、有機FET、単一分子素子など、機能性分子を用いたデバイ 　　スの研究が盛んに行われている。それらの機能は、分子自体の電子状態はもち 　　ろん、分子のコンフォメーションや配列状態、基板表面との相互作用などによ 　　って大きく変わる。そこで我々は、走査型トンネル顕微鏡(STM)を用いた高分解 　　能実空間観察技術を駆使し、金属表面に吸着した機能性ナノ分子のさまざまな 　　性質を明らかにしようとしている[1]。本講演では、金属表面に吸着したオリゴ 　　チオフェン、ポルフィリン、イリジウム錯体などのナノサイズ分子について、 　　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 　　する。特に、内容を(1)吸着分子のコンフォメーション解析や異性体識別、電子 　　状態計測などを中心にした単一分子観察[2]、(2)表面拡散や分子間相互作用[3]、 　　(3)分子を表面で組み上げる超分子自己組織化に分けて概説する予定である。 　　[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 Abstract： 　　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 Abstract： 　　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 Abstract： 　　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) 　　　　　５．金属・有機半導体界面における真空レベルオフセットの理論的背景 　　　　　６．Carrier Injection Barriers 　　　　　７．有機半導体FET（OFET）の概要 　　　　　８．まとめ 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 Abstract： 　　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).