Ultrafast Spectroscopy and Other Applications of Lasers in Chemistry

宾夕法尼亚大学的Robin Hochstrasser得到了实验物理化学项目的支持，继续他对液体超快动力学的研究。飞秒激光光谱技术将涉及两个中心主题：化学反应的溶剂控制和分子激发的弛豫。需要开发的具体技术包括低频瞬态红外光谱；太赫兹光谱在分子泵-探针实验中的低频运动探测以及对液体样品的时间分辨x射线散射。重点是溶剂辅助单分子和双分子反应动力学和电子和振动弛豫。量子化学计算的势能面和经典分子动力学模拟也将进行。研究凝聚态中能量激发分子从一种分子异构体结构向另一种分子异构体结构的转变，将极大地扩展我们对复杂分子如何经历内部重排以及这些重排如何由周围溶剂介导的知识。

Robin Hochstrasser of the University of Pennsylvania is supported by the Experimental Physical Chemistry Program to continue his studies on ultrafast dynamics in liquids. Femtosecond (fs) laser spectroscopic techniques will be brought to bear on two central themes: solvent control of chemical reactions and the relaxation of molecular excitations. Specific techniques to be developed include fs transient infrared spectroscopy at low frequencies; terahertz spectroscopy to probe low frequency motions in molecular pump-probe experiments; and fs time-resolved X-ray scattering on liquid samples. Focus is on solvent-assisted uni- and bimolecular reaction dynamics and electronic and vibrational relaxation. Quantum chemical calculations of the potential energy surfaces and classical molecular dynamics simulations will also be carried out. The study of the transformation of energetically excited molecules in condensed phases from one molecular isomeric configuration to another will significantly expand our knowledge of how a complex molecule undergoes internal rearrangements and how these are mediated by a surrounding solvent.