ISSP - The institute for Solid State Physics

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Yamamuro Group

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We are studying chemical physics of complex condensed matters, especially glasses and supercooled liquids, water and related materials, ionic liquids, and nanoparticles of hydrogen storage metals. Glass transition is a mysterious phenomenon in which liquids solidify without structural change. This is one of big and long-standing issues in physics. Water, which is the most familiar material for us, exhibits various unique phenomena caused by hydrogen bonds. Ionic liquids have nanometer-size domains and hierarchical dynamics generated by competing electrostatic and van der Waals interactions. Hydrogen atoms in metal nanoparticles give rise to unusual structure and dynamics caused by the surface effects and resultant distorted potential energy surfaces. These substances are investigated by neutron scattering, x-ray diffraction, heat capacity, and dielectric measurements. Our aim is to find simple (?) rules involved in complex systems from the three different points of view, i.e., structure, dynamics, and thermodynamic.

Neutron powder diffraction pattern and the result of the Rietveld analysis for nanoparticles of palladium deuteride (PdD0.36). We found that D atoms occupy not only the O sites (only this site for bulk samples) but also the T-sites at around the surface of the nanoparticles.
Overall relaxation map of C8mimTFSI. These relaxation times were determined by quasielastic neutron scattering experiments using 3 spectrometers. Four different relaxation modes exist in a wide time range between 1 ps and 100 ns.

Research Subjects

  1. Dynamics of disordered condensed systems, such as glass transitions and boson peaks
  2. Structure and dynamics of water and related materials such as hydrated porous crystals
  3. Thermal and dynamical properties of room-temperature ionic liquids
  4. Thermal and dynamical properties of hydrogen storage solids