Resonance Raman Studies of Excited-State Structure and Dynamics

在这个项目中的物理化学计划的化学 作者：Richard A.加州大学的Mathies在 伯克利将进行一系列调查，以确定地面 激发态核动力学和结构变化， 凝聚相光化学和光生物学反应， 了解它们的分子反应机制。 模式特定的 原子核动力学是在原子核激发后立即发生的， 光化学活性系统将通过测量和 绝对激光共振拉曼振动散射分析 强度 皮秒时间分辨共振拉曼和吸收 光谱学将被用来研究基态的动力学 光产物的形成与基态的结构和弛豫 光化学中间体 将开展以下研究。第一章 光化学开环、闭环和1，7氢转移反应 2）蛋白质环境的反应， 细菌视紫红质和藻胆蛋白中的电子 激发/光异构化它们结合的发色团辅基 3）视色素的光激发 光化学电子转移 反应在细菌光合反应中心，和5） 四吡咯发色团的光化学激发机理 植物光敏色素是植物中的感光色素。 这些研究探索了光与光之间相互作用的基本原理 和光生物活性材料，并将有助于我们的 了解发生在生物体内的基本过程 和无生命的生命系统。 本研究的总体目标是 找到关于化学反应如何在凝聚态中发生的一般原理 相光化学体系。

In this project in the Physical Chemistry Program of the Chemistry Division, Professor Richard A. Mathies of the University of California at Berkeley will conduct a series of investigations to determine the ground and excited-state nuclear dynamics and structural changes that occur in condensed phase photochemical and photobiological reactions and thereby understand their molecular reaction mechanisms. The mode-specific nuclear dynamics that occur immediately after excitation of a photochemically active system will be determined by measuring and analyzing absolute laser resonance Raman vibrational scattering intensities. Picosecond time-resolved resonance Raman and absorption spectroscopy will be used to study the kinetics of ground-state photoproduct formation and the structures and relaxation of ground-state photochemical intermediates. The following studies will be pursued. 1) Photochemical ring-opening, ring-closing and 1,7 hydrogen shift reactions of cyclic polyenes; 2) the response of protein environment in bacteriorhodopsin and in phycobiliproteins to the electronic excitation/photoisomerization of their bound chromophoric prosthetic groups will be studied; 3) the photoexcitation of visual pigment rhodopsin will be investigated; 4) the photochemical electron transfer reaction in bacterial photosynthetic reaction centers, and 5) the mechanism of photochemical excitation of tetrapyrrole chromophore in phytochrome, the light sensing pigment in plants, will be examined. These investigations probe the basics of the interaction between light and photo-biologically active materials and will contribute to our understanding of the fundamental processes which take place in animate and inanimate living systems. The overall goal of this research is to find general principles about how chemical reactions occur in condensed phase photochemical systems at room temperature.