标 题:
Dalian coherent light source: the current status and applications
&
Ultrafast decay dynamics of water molecules excited to high-lying electronic states
时 间: 2019 年 11 月 1 日 10 : 30 - 12 : 00
地 点: 光电信息大楼 C112
报告人: 吴国荣 正高级工程师 (中科院大连化物所)
邀请人: 彭家晖 教授
报告摘要:
In this talk, I will cover two related topics: 1) Dalian coherent light source: the current status and applications; and 2) Ultrafast decay dynamics of water molecules excited to high-lying electronic states.
Dalian coherent light source (DCLS) is a free electron laser facility, dedicated at VUV wavelength range of 50-150 nm. DCLS operates with two alternative modes: 100 fs and 1 ps, targeting at studies in the time- and frequency-domains, respectively. DCLS started to serve users 24/7 from 2018. Wide applications have been found in the studies of physical, chemical and biological processes. In this talk, I will introduce the current status of DCLS, including main specs of the FEL output and endstations installed. Typical experiments performed so far will also be briefly mentioned.
Photochemistry of water in the gas phase is one of the most important, yet challenging topic in molecular reaction dynamics. It also serves as an ideal model system to study complicated excited-state dynamics of polyatomic molecules. Excited-state dynamics of water molecules has been intensively studied, both experimentally and theoretically, for more than four decades and rich information has been obtained from various studies, such as absorption spectra, resonance-enhanced multiphoton ionization (REMPI) spectra, OH product fluorescence excitation spectra, H product action spectra and photodissociation dynamics, time-resolved excited-state dynamics, etc. Among these studies, experiments are mainly limited to the frequency domain, due to the lack of the wavelength-tunable fs laser source in the VUV range. In the last couple of years, we have studied the ultrafast decay dynamics of water molecules excited into the C, D, D’, D’’ and F states, by using two-photon excitation and time-resolved photoelectron imaging (TRPEI) techniques. Extensive information on the ultrafast decay dynamics of these higher-lying excited states has been derived.
报告人介绍
吴国荣,中国科学院大连化学物理研究所正高级工程师,博士生导师。1998年于中国科学技术大学获学士学位,2005年于中国科学院大连化学物理研究所获博士学位,毕业后留所工作。2007年10月至2008年5月在加拿大女王大学做博士后研究,2008年5月至2011年10月在加拿大国家科学研究院任助理研究员。