only a Japanese version



2013年3月27日(水)14:30 理学研究科Z302講義室

Ultrafast molecular reaction dynamics on insulating thin films and supported metal particles
Prof. Thorsten M Bernhardt
Institute of Surface Chemistry and Catalysis
University of Ulm, Germany

Oxide supported metal particles are of utmost importance in chemical catalysis. Size-selected metal clusters on single crystal substrates and well-defined ultra-thin oxide films represent versatile model systems for the investigation of the physical and chemical properties of such nano-systems [1]. We employ femtosecond laser pump-probe mass spectrometry with resonance enhanced multi-photon ionization detection to reveal the time-dependent photo-induced reaction dynamics of adsorbate molecules as a function of the oxide film thickness and the cluster size [2-4]. In this experiment, methyl halide molecules serve as photochemical model systems. The photodissociation on the surface can initiate subsequent bimolecular reactions of the photofragments with co-adsorbed molecules. Via time-, mass-, and velocity-resolved monitoring of intermediate and product species it is possible to obtain insight into the complex dynamics of the photoinduced surface reaction on the different substrates [5-7].

1 M. E. Vaida, T. M. Bernhardt, C. Barth, F. Esch, U. Heiz, and U. Landman, Phys. Status Solidi B, 2010, 247, 1001.

2 M. E. Vaida, P. E. Hindelang, and T. M. Bernhardt, J. Chem. Phys., 2008, 129, 011105.

3 M. E. Vaida and T. M. Bernhardt, ChemPhysChem, 2010, 11, 804.

4 M. E. Vaida and T. M. Bernhardt, Rev. Sci. Instrum., 2010, 81, 104103.

5 M. E. Vaida, T. Gleitsmann, R. Tchitnga, and T. M. Bernhardt, Phys. Status Solidi B, 2010, 247, 1139.

6 M. E. Vaida and T. M. Bernhardt, Eur. J. Phys. D, 2009, 52, 119.

7 M. E. Vaida and T. M. Bernhardt, Faraday Discuss., 2012, 157, 437.

Modification of energy-transfer processes in photosynthetic organisms to adapt to light conditions
Prof. Seiji Akimoto
Molecular Photoscience Research Center
Kobe University, Japan

In photosynthetic organisms, the interactions within and among pigment-protein complexes are modified in response to changes in light conditions. We analyzed excitation energy transfer processes among phycobilisome, photosystem II, and photosystem I in the cyanobacterium Arthrospira (Spirulina) platensis. The cells were grown under lights with different spectral profiles and under different light intensities. The energy-transfer characteristics were evaluated using steady-state fluorescence and picosecond time-resolved fluorescence spectroscopies. We discuss the differences in energy-transfer processes under different cultivation and light conditions.