| 日時: |
2008-01-28 14:00 - 15:00 |
| 場所: |
4号館2階輪講室２ |
| 会議名: |
放射光セミナー「Tracking Photoswitching Dynamics of Molecules in Materials」 |
| 講演者: |
Prof. Herve Cailleau (Institute of Physics of Rennes, University of Rennes 1-CNRS) |
| 講演言語: |
英語 |
| URL: |
http://pfwww.kek.jp/pf-seminar/index.html |
| アブストラクト: |
Light tuning of the charge and/or spin states of molecules in a solid material is a promising target. Contrary to dilute solutions, all the constituent molecule in solids can be photoactive, and the medium is not passive but active. In other words, due to cooperative intermolecular interactions, light can induce self-amplification and self-organization processes, offering the possibility for the material to be directed between different electronic and structural order, a so-called photo-induced phase transition. This opens new avenues for light-control of various photoswitchable functions (magnetic, optical, conduction,…), with some direct consequences for future developments communication and information technologies.
Another step is the possibility to directly observe in real time the assembly of molecules moving and transforming by using the emerging fast and ultra-fast X-ray scattering techniques. In this talk I will give a small overview of new concepts which can be proposed for this emerging field. This will be illustrated by two situations in relation with the recent results obtained by the progress in X-ray and optical techniques under cw or pulsed laser excitation: - first, the photo-steady state of spin transition with respect to the strength of cooperative interactions (crossover or phase separation) which provides a new kind of non-linear chemical dynamics (self-organization, bistability,…); - the use of ultra-short laser pulse to trigger ultra-fast photo-induced phase transition in charge-transfer and spin transition materials which represents a next step ensuing the now established field of femtochemistry A fascinating feature is to directly observe the change from coherent deterministic dynamics at ultra-short time to stochastic thermal kinetics after the lattice thermalization.
Many of there results presented in this talk was obtained within the Non-equilibrium Dynamics ERATO/JST project.
General references
1. Photoinduced Phase Transitions, K. Nasu ed., World Scientific (2004).
2. Photo-Induced Phase Transition and their Dynamics, S. Koshihara and M.Kuwata-Gonokami eds, special topics in J. Phys. Soc. Jpn 75, 011001-011008 (2006).
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