Institute of Multidisciplinary Research for Advanced Materials, Tohoku University


LAST UPDATE 2021/05/19

  • 研究者氏名
    Researcher Name

    高岡毅 Tsuyoshi TAKAOKA
    講師 Lecturer
  • 所属
    Professional Affiliation

    Institute of Multidisciplinary Research for Advanced Materials, Tohoku University

    計測研究部門 走査プローブ計測技術研究分野
    Division of Measurements, Advanced Scanning Probe Microscopy
  • 研究キーワード
    Research Keywords

    Surface Science
    Molecular Adsorption
    Catalysis Reaction
    Infrared Spectroscopy
Research Subject
Exploration of mechanism of molecular motion on solid surfaces

研究の背景 Background


There have been continuous researches of the friction for a long time. The researches are now focusing on the phenomena at nano or molecular level, since they are directly related to the formation mechanism of self-assembled molecular films and nanostructures, as well as catalytic reactions of adsorbates. Compared to the studies of atomicscale friction in physisorption systems, less have been examined on chemisorbed molecules despite their importance in applications.

研究の目標 Outcome


We have shown a method to measure the friction of a single molecule chemisorbed on a surface. In the method, energycontrolled rare gas atoms are incident on the molecules. The translational energy is transferred to the adsorbates through mechanical collisions, and the adsorbates are displaced so that they can reach step sites. Molecules adsorbed at step site and terrace site were distinguished by infrared spectroscopy. Our object is the estimation of friction coefficient of molecules, and decay of kinetic energy of CO molecules.

研究図Research Figure

Fig.1. Schematic diagram of a Pt(997) surface after the surface is exposed to CO molecules and subsequently to rare gas atoms. CO molecules are displaced on the surface when incident rare gas atoms have a sufficiently high translational energy to permit lateral motion of CO molecules. Fig.2. A series of FTIR spectra obtained after a Pt(997) surface is exposed to CO molecules and subsequently to Ar atoms having a translational energy of 0.95 eV at θi=45° . The CO coverage was estimated to be 0.033 ML. The amounts of Ar atoms in (a), (b), (c), (d), (e), and (f) are 0, 2.1, 4.2, 6.34, 10, and 21 x 1015 cm-2, respectively Fig.3. A schematic of the relation between the displacement and the translational energy of CO after obtaining a translational energy, where the friction coefficient of 8 x 1012 sec-1 is used. The transient surface diffusion length of CO on the Pt(997) surface reported previously is shown as a dotted circular arc.

文献 / Publications

T. Takaoka and T. Komeda, Phys. Rev. Lett. 100 (2008) 046104.