报告题目：Ultrafast photoemission studies of the physical basis for plasmonically enhanced photocatalysis

报告人：Prof. Hrvoje Petek（University of Pittsburgh）

报告时间：5月13日（周五）下午4:00

报告地点：物理学院新楼五楼多功能厅

报告摘要：Excitation of plasmon resonances in metallic nanoparticles can enhance a variety of electromagnetic phenomena ranging from surface enhanced Raman scattering to photocatalysis. We employ multiphoton photoemission spectroscopy (mPP) with broadly tunable femtosecond excitation to investigate the photoemission mechanisms for the clean and metal nanoparticle (Ag and Au) decorated TiO2 and graphite surfaces. On reduced TiO2 surfaces, 2PP proceeds from t2g symmetry Ti-3d defect states via a resonance with unoccupied eg states.1 In the case of graphite, mPP is predominantly of thermionic nature due to ineffectively screened Coulomb interactions, which are responsible for extremely efficient electron-electron scattering. In the presence of metal nanoparticles, the mPP processes are significantly enhanced, and provide clues to plasmon-substrate coupling that could be responsible for photocatalysis.

报告人简介：Prof. Hrvoje Petek is the RK Mellon Chair Professor of Physics and Astronomy, and Professor of Chemistry at the University of Pittsburgh. He obtained his BS in 1980 at MIT, and PhD in 1985 at U.C. Berkeley, both in Chemistry. In 2000, he became a Professor of Physics, and later Professor of Chemistry, as well as the co-Director of the Petersen Institute for NanoScience and Engineering at the University of Pittsburgh (2005-2012). In 2014, he was appointed as the Richard King Mellon Chair Professor of Physics and Astronomy, the most prestigious professor Chair at the University. Currently he is also a member of the National Research and Development Agency Committee of Japan. Professor Hrvoje Petek was elected as a Fellow of the American Physical Society in 2003.

邀请人：丰敏教授