Photoinitiated Reactions in Ultracold Helium Clusters

在这个由化学部实验物理化学计划资助的项目中，Wittig将研究涉及嵌入氦滴中的多原子分子的光引发过程，He(N)。这项工作站在当代物理化学的前沿，它的目标是定量地了解在具有特殊特征的液氦浴中发生的松弛和反应过程。为气相光化学开发的广泛知识将用于对凝聚介质中的过程进行建模。新的化学体系，几乎不受周围环境的干扰，但在喷射膨胀中难以形成和研究，将被研究。这项研究涉及捕获在液氦超冷液滴及其表面的分子的性质。这种嵌入或附着的分子可以自由旋转，但旋转参数不同于描述分子在稀薄气体中旋转的参数。因此，由于其高反应性而很难用传统方法制备的分子体系可以进行研究。这些高活性物种在化学反应中起着重要作用，拟议的研究将提供以其他方式无法获得或很难获得的信息。这项研究将在研究生和本科生以及博士后研究助理的协助下进行。这些合作者将获得物理化学前沿领域的技能和知识，为他们在工业、政府研究实验室或学术界进行深入研究或就业做好准备。

In this project funded by the Experimental Physical Chemistry Program of the Chemistry Division, Wittig will investigate photoinitiated processes that involve polyatomic molecules embedded in helium droplets, He(n). This work stands at the forefront of contemporary physical chemistry and its goal is to obtain quantitative understanding of relaxation and reactive processes that take place in an exceptionally well-characterized bath of liquid helium. Broad knowledge developed for gas phase photochemistry will be used in the modeling of processes in the condensed medium. New chemical systems, almost unperturbed by surroundings, but difficult in being formed and studied in jet expansions, will be investigated.This research deals with the properties of molecules trapped in and on the surfaces of ultracold droplets of liquid helium. Such embedded, or attached, molecules can rotate freely, but with a rotational parameter that is different from the one that characterizes the rotation of molecules in a dilute gas. Molecular systems that are very difficult to prepare by conventional methods due to their high reactivity can thereby be made accessible to study. Such highly reactive species play an important role in chemical reactions and the proposed research will provide information not otherwise available or very difficult to obtain. The research will be conducted with the assistance of graduate and undergraduate students, and postdoctoral research associates. These collaborators will acquire skills and knowledge in a forefront area of physical chemistry that prepares them for advanced studies or employment in industry, government research laboratories, or academia.