报告题目：Mode assignments for THz vibrational spectra of molecular crystals
　　报告人：张峰博士
　　报告人单位: Molecular Photoscience Research Center, Kobe University, Japan
　　报告时间： 2017年12月21日（周四）上午10:00
　　报告地点：嘉定园区学术活动中心307房间
　　
　　报告摘要：
　　Terahertz (THz) spectroscopic measurement of molecular crystals have become a routine practice in many laboratories, but the interpretation of the measured peaks is far from routine. We will introduce our progresses in the past decade in solving one of the basic problems—mode assignment—through the interplay of THz spectroscopy and solid-state ab initio theory. Quantitative agreements between experiment and theory have been achieved for a broad spectrum of prototypical molecular systems. A quantitative mode analysis method has been established for characterizing the origin of any THz mode of interest. On this basis, we will illustrate the power of THz spectroscopy in tackling some major problems of X-ray crystallography. Two examples will be specifically elucidated. One is the determination of the positions of hydrogen atoms in polymer crystals; the other is the deduction of the packing information in disordered molecular crystals. We will finally outlook the applications of THz spectroscopy to revealing the structure-encoded vibrations of proteins and to studying anharmonicity of molecular phonon modes.