X-ray diffraction experiments on ultrafast photo-chemical reactions in solid state and solution with regard to biological applications

近年来，光谱学的时间分辨率已经扩展到几飞秒的范围，达到了化学和生物反应速度的极限。不幸的是，目前的光谱方法不允许直接访问快速结构变化。由于结构信息对于理解生物和化学反应至关重要，因此需要具有时间分辨率在亚皮秒范围内的时间分辨结构方法。在这个项目中，我们计划研究与光化学反应相关的超快结构变化，并长期将这些实验扩展到生物聚合物（如蛋白质和肽）的动力学研究。首先，我们计划建立一个基于强飞秒光脉冲等离子体产生的亚皮秒x射线源，以优化该源以进行测试衍射实验，并随后研究分子晶体或客体-宿主系统中的超快光异构和光解离过程。

The temporal resolution of optical spectroscopy has been extended recently to the range of a few femtoseconds where the limits of the chemical and biological reaction speed is reached. Unfortunately the present spectroscopic methods do not allow the direct access to fast structural changes. Since structural information is of fundamental importance for the understanding of biological and chemical reactions time-resolved structural methods with temporal resolution in the sub-picosecond range is required. In this project we plan to investigate ultrafast structural changes related to photochemical reactions and on the long term to extend these experiments towards the study of the dynamics of biopolymers such as proteins and peptides. At the beginning we plan to build a sub-picosecond x-ray source based on plasma generation via strong femtosecond light pulses, to optimize this source to allow test diffraction experiments and subsequently to study ultrafast photo-isomerization and photo-dissociation processes in molecular crystals or guest-host systems.