研究室及び学会主催のセミナー (Seminar and invited talk)

Invited talk
 日時: 平成28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
 日時: 平成28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
 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
 日時: 平成26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)

触媒学会 つくば地区講演会 (2014年度)

触媒学会 つくば地区講演会 (2013年度)

触媒学会 つくば地区講演会 (2012年度)

Invited talk
 日時: 平成24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
 日時: 平成24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).

触媒学会 つくば地区講演会 (2011年度)

Invited talk
 日時: 平成23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
 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)


触媒学会 つくば地区講演会 (2010年度)


【研究会趣旨】 本研究会は表面・界面の物理的・化学的性質を分光学的に探求する 実験および理論の研究者が集まり、全参加者が泊り込んで集中的に 議論することで、情報の交換、問題意識の共有を図ることをねらい、 年1回開催されています。
 表面振動分光、走査型プローブ顕微鏡、各種光電子分光など、 表面・界面に敏感な分光手法を中心とした、最新の研究成果を講演 していただき、多様なバックグラウンドを持つ研究者が討論を通して 相互理解し、新たな共同研究が生まれることを目的としています。
 なお、本年度も恒例になりましたStudent Prizeを設けます。 学生の皆様の積極的なご応募を歓迎いたしますので、 どうぞよろしくお願い致します。

日時: 平成22年12月3日(金)13時頃 ~ 4日(土)13時頃

場所: 筑波山京成ホテル(〒300-4352 つくば市筑波1つつじヶ丘)    * つくばエクスプレス つくば駅から送迎バスを用意します。

特別講演: 花栗哲郎 氏(理化学研究所専任研究員)

協賛: 日本表面科学会,触媒学会


参加費 : 20000円
(内訳) 参加登録費 : 10000円     宿泊費(2食込み) : 10000円

発表登録締切日: 10月29日(金)
参加登録締切日: 10月29日(金)

(6)口頭orポスター(7)student Prizeの有無

Microsoft wordのdocファイルまたはpdfファイルで近藤(takahiro[at]ims.tsukuba.ac.jp)まで

(2)Student Prizeに該当する方
Microsoft wordのdocファイルまたはpdfファイルで近藤(takahiro[at]ims.tsukuba.ac.jp)まで


中村潤児 (Tel/Fax: 029-853-5279 E-mail: nakamura@ims.tsukuba.ac.jp)
近藤剛弘(Tel/Fax: 029-853-5934 E-mail: takahiro@ims.tsukuba.ac.jp)

日時:  2010年9月7・8日(火・水)10:00~
場所:  筑波大学 総合研究棟B 110室 (注 第1講のみ112室)
主催:  触媒学会(表面化学と触媒設計の融合研究会)
共催:  日本化学会(依頼中)
協賛:  日本表面科学会
参加費: (テキスト代、懇親会費500円含む)       1日のみ 一般(会員 \7,000、非会員 \10,000)、学生 \2,000       2日間受講 一般(会員 \10,000、非会員 \15,000)、学生 \3,000
申込方法: (1)氏名(2)所属(3)連絡先(4)参加日(5)会員・非会員・学生の種別(6)懇親会への参加の有無        を明記し、FAXまたはE-mailで下記連絡先までお申し込み下さい
連絡先:  触媒学会「表面化学と触媒設計の融合研究会」世話人代表        筑波大学大学院数理物質科学研究科 中村潤児        Tel/Fax: 029-853-5279         E-mail: nakamura*ims.tsukuba.ac.jp (*を@に変えて送信してください。)
申込期限:  8月24日(火) (申し込みが80名に達した時点で締切といたします)


9:50 開講・連絡・趣旨説明  
10:00-11:30 中村 潤児(表面反応概論)  
11:30-12:30 昼食  
12:30-14:00 福井 賢一(表面構造と表面電子状態)  
14:15-15:45 吉信 淳(表面ダイナミクス)   
16:00-17:30 中村 潤児(モデル触媒概論)  
17:30-18:30 懇親会
10:00-11:30 福井 賢一(酸化物表面化学)  
11:30-12:20 昼食  
12:20-13:50 吉信 淳(半導体表面化学)  
14:05-15:35 近藤 寛(金属表面化学)  
15:50-17:25 犬飼 潤治(電極表面化学)  
17:25-17:30 閉講・連絡・今後の予定

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).

第2回 表面化学サロン
日時:  2009年 12月22日 13時30分~19時

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.

日時:  2008年 12月15日 13時~19時

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 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
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 very a 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).