{"93161":{"#nid":"93161","#data":{"type":"event","title":"(08-0701) Prof. Koichi Iwata, University of Tokyo","body":[{"value":"\u003Cp\u003EProf. Koichi Iwata, University of Tokyo\n\u003C\/p\u003E\n\u003Cp\u003ETracing \u0022loose electrons\u0022 - New physical chemistry with femtosecond time-resolved near-infrared spectroscopy\n\u003C\/p\u003E\n\u003Cp\u003EAbstract\n\u003C\/p\u003E\n\u003Cp\u003EWe examine \u0022elementary processes\u0022 of solution-phase chemical reactions with various time-resolved spectroscopies. In this presentation, I report on femtosecond time-resolved fluorescence spectroscopy and picosecond time-resolved Raman spectroscopy.\n\u003C\/p\u003E\n\u003Cp\u003EBy using femtosecond time-resolved near-infrared spectrometer that covers the spectral rage of 900 to 1500 nm, we trance the dynamics of \u0022loose electrons\u0022, electrons loosely bound to the nuclei, with a femtosecond time- resolution. Because the probe wavelength is longer, it is possible to measure the time-resolved spectra of scattering powder samples with the transmission geometry, by keeping the femtosecond time-resolution in tact. We measure the migration and decay dynamics of charge carriers generated in photocatalytic TO2 powders. The carrier dynamics changes largely depending on the crystal form (anatase or rutile) and the diameter. When Pt is loaded as a co-catalyst, the photogenerated electrons are transferred to Pt in 2 ps. When the TiO2 powders are immersed in an ionic liquid, the decay process of the generated carriers is accelerated from those in vacuum, in air, or in water. We also examine the intramolecular charge transfer reaction in 9,9\u0027-bianthryl. We discuss the detailed mechanism of the photoinduced charge transfer reaction in polar and nonpolar environments based on the experimental results from femtosecond time-resolved near-infrared spectroscopy.\n\u003C\/p\u003E\n\u003Cp\u003EWhen a molecule in solution is photoexcited to one of its electronically excited states with larger energy than required for the 0-0 transition, the excess energy is deposited to the vibrational manifold. The solute molecule then starts cooling down by dissipating the excess energy to the surrounding solvent molecules. By monitoring the cooling process of the solute, it is possible to trance the solute- solvent energy transfer process. We trace the cooling kinetics of the solute by measuring the picosecond time- resolved Raman spectra of the first excited singlet (S1) state of trans-stilbene. The trans-stilbene molecule serves as a good thermometer with a time-resolving capability of a few picoseconds. We found that there was a good correlation between the cooling rate of S1 trans-stilbene and the thermal diffusivity of the solvent in ten molecular solvents. Little is known, however, about the energy transfer mechanism in room-temperature ionic liquids. We examine the cooling kinetics of S1 trans-stilbene in the ionic liquids. It is interesting to know how the possible \u0022local structures\u0022 in the ionic liquids, an assumption not proved in a rigorous sense but supported by increasing number of researchers, affect the microscopic solute-solvent or solvent-solvent energy transfer.\n\u003C\/p\u003E\n\u003Cp\u003EBiography\n\u003C\/p\u003E\n\u003Cp\u003EName:\tKoichi IWATA\u003Cbr \/\u003E\nTitle:\tAssociate Professor\u003Cbr \/\u003E\nInstitute: Research Centre for Spectrochemistry, School of Science, The University of Tokyo\u003Cbr \/\u003E\nAddress: 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, Japan\u003Cbr \/\u003E\nE-mail:\t\u003Ca href=\u0022mailto:iwata@chem.s.u-tokyo.ac.jp\u0022\u003Eiwata@chem.s.u-tokyo.ac.jp\u003C\/a\u003E\u003Cbr \/\u003E\nTelephone: 81-3-5841-4600\u003Cbr \/\u003E\nFAX:\t   81-3-5800-4540\n\u003C\/p\u003E\n\u003Cp\u003EEducation:\u003Cbr \/\u003E\nThe University of Tokyo, Japan\tB.S.\t1984\tChemistry\u003Cbr \/\u003E\nThe University of Tokyo, Japan\tM.S.\t1986\tPhysical Chemistry\u003Cbr \/\u003E\nThe University of Tokyo, Japan\tDr.Sci.\t1989\tPhysical Chemistry\u003Cbr \/\u003E\nTitle of the doctoral thesis, \u0022Construction of a Microsecond Time-resolved Infrared Spectrometer and Its Applications\u0022\n\u003C\/p\u003E\n\u003Cp\u003EProfessional Experience:\u003Cbr \/\u003E\nPostdoctoral Fellow, Department of Chemistry, The Ohio State University, Columbus, Ohio, USA\t1989-1990\u003Cbr \/\u003E\nResearch Associate, Molecular Spectroscopy Laboratory, Kanagawa Academy of Science and Technology, Kawasaki, Japan\t1991-1997\u003Cbr \/\u003E\nAssociate Professor, Department of Chemistry, School of Science, The University of Tokyo, Tokyo, Japan\t1997-2001\u003Cbr \/\u003E\nAssociate Professor, Research Centre for Spectrochemistry, School of Science, The University of Tokyo, Tokyo, Japan\t2001-present\n\u003C\/p\u003E\n\u003Cp\u003EFor more information contact \u003Ca href=\u0022mailto:robert.dickson@chemistry.gatech.edu\u0022\u003EProf. Rob Dickson\u003C\/a\u003E (404-894-4007).\u003C\/p\u003E","summary":null,"format":"limited_html"}],"field_subtitle":"","field_summary":[{"value":"Prof. Koichi Iwata, University of Tokyo\n\nTracing \u0022loose electrons\u0022 - New physical chemistry with femtosecond time-resolved near-infrared spectroscopy","format":"limited_html"}],"field_summary_sentence":[{"value":"Prof. Koichi Iwata, University of Tokyo"}],"uid":"27275","created_gmt":"2008-05-20 00:00:00","changed_gmt":"2016-10-08 01:57:20","author":"Shirley Tomes","boilerplate_text":"","field_publication":"","field_article_url":"","field_event_time":{"event_time_start":"2008-07-01T16:00:00-04:00","event_time_end":"2008-07-01T17:00:00-04:00","event_time_end_last":"2008-07-01T17:00:00-04:00","gmt_time_start":"2008-07-01 20:00:00","gmt_time_end":"2008-07-01 21:00:00","gmt_time_end_last":"2008-07-01 21:00:00","rrule":null,"timezone":"America\/New_York"},"extras":[],"related_links":[{"url":"http:\/\/www.chem.s.u-tokyo.ac.jp\/english\/index.html","title":"Prof. Koichi Iwata"}],"groups":[{"id":"85951","name":"School of Chemistry and Biochemistry"}],"categories":[],"keywords":[{"id":"5898","name":"biological chemistry"}],"core_research_areas":[],"news_room_topics":[],"event_categories":[{"id":"1795","name":"Seminar\/Lecture\/Colloquium"}],"invited_audience":[],"affiliations":[],"classification":[],"areas_of_expertise":[],"news_and_recent_appearances":[],"phone":[],"contact":[{"value":"\u003Cstrong\u003EShirley Tomes\u003C\/strong\u003E\u003Cbr \/\u003EChemistry \u0026amp; Biochemistry\u003Cbr \/\u003E\u003Ca href=\u0022http:\/\/www.gatech.edu\/contact\/index.html?id=st81\u0022\u003EContact Shirley Tomes\u003C\/a\u003E\u003Cbr \/\u003E\u003Cstrong\u003E404-894-0591\u003C\/strong\u003E","format":"limited_html"}],"email":[],"slides":[],"orientation":[],"userdata":""}}}