Transient Stimulated Emission Pumping Studies of Photodissociation Dynamics

9304691在化学系物理化学项目中，Y.位于伯克利的加州大学的Chen将进行一项研究计划，以系统地了解分子内能量转移和化学反应之间的相互作用。 为此，他发明的飞秒时域瞬态受激发射泵浦（TSEP）光谱新技术将应用于两个模型系统，臭氧和亚硝酸甲酯，以获得这些物种的光致碎裂过程中的实时发射光谱。 化学反应和解离过程的细节发生在皮科到飞秒的时间尺度上，这一领域的研究处于当代物理化学的前沿。 这些过程所提出的问题之一是，激发特定分子振动态的能量如何在分子内重新分布，从而导致分子通过特定化学键的断裂而解离，或导致分子重排成不同的构象结构。 STEP方法与目前用途：使用的其他技术相比具有几个明显的优点：它能够提供时间和频率信息，谱分配是明确的，并且它具有高灵敏度。 这使得STEP方法成为研究多原子体系中能量传递和化学反应的理想工具。 ***

9304691 Chen In this project of the Physical Chemistry Program in the Chemistry Division, Prof. Y. Chen of the University of California at Berkeley will pursue a program of research to provide a systematic understanding of the interplay between intramolecular energy transfer and chemical reactions. To this end the new technique of femtosecond time-domain Transient Stimulated Emission Pumping (TSEP) spectroscopy invented by him will be applied to two model systems, ozone and methylnitrite to obtain real-time emission spectra during the photofragmentation of these species. %%% The details of chemical reaction and dissociation processes occur at pico- to femtosecond time scales and research in this field is at the forefront of contemporary physical chemistry. Among the questions posed by these processes is how the energy which excites a specific molecular vibrational state redistributes itself within the molecule to result in the dissociation of the molecule by the breaking of a specific chemical bond or in the molecular rearrangement into a different conformational structure. The STEP method possesses several distinct advantages over other techniques currently in use: it is capable of furnishing both time and frequency information, the spectral assignments are unambiguous, and it has high sensitivity. These make the STEP method an ideal tool for studying the energy transfer and chemical reactions in polyatomic systems. ***