State, Time and Velocity Resolved Photofragment Translation-al Spectroscopy of Organic Iodides in the Gas Phase and in Solvated Clusters

在化学系实验物理化学计划的这个项目中，将研究分离的和溶剂化的分子碘和有机碘的光解离，并将通过三组实验分析其动力学。第一套将涉及开发一维投影技术，以确定从解离过程中确定碘碎片的速度分布。第二组将涉及飞秒泵浦-探测技术，以测量光碎片作为离解极限以上过剩能量的函数的动能，以获得关于离解势能面形状的信息。第三组将涉及对溶剂化的碘离子的研究，这些离子被光解并用质量选择离子动能谱进行检测，由此推导出碎裂动力学。研究多原子分子的光解离过程，即多原子分子在光作用下的碎裂，可以揭示许多关于塑造分子行为的电子力。特别是，可以确定处于激发电子能态的分子的寿命以及当电子激发的分子分解时过剩能量在碎片之间的分配。这些信息反过来又可以给出控制解离碎片行为的势能的详细图景，这反过来又可以与凝聚(液体或固体)相中物种的行为有关。这种多原子分子光解的实验光谱研究是当前项目的目标。

In this project in the Experimental Physical Chemistry Program of the Chemistry Division, photodissociation of isolated and solvated molecular iodine and organic iodides will be studied, and the dynamics will be analyzed in three sets of experiments. The first set will involve the development of a one-dimensional projection technique to determine the velocity distribution of the iodine fragment from the dissociation processes. The second set will involve femtosecond pump-probe techniques to measure the kinetic energy of the photofragments as a function of excess energy above the dissociation limit to gain information on the shape of the dissociating potential energy surface. The third set will involve the study of solvated iodine ions which are photodissociated and examined using mass-selected ion kinetic energy spectroscopy, from which the fragmentation dynamics are deduced. %%% The study of photodissociation processes of polyatomic molecules, that is, the fragmentation of molecules with many atoms using light, can reveal a great deal about the electronic forces which shape the behavior of the molecules. In particular, the lifetimes of the molecules in an excited electronic energy state as well as the partitioning of the excess energy among the fragments when an electronically excited molecule decomposes can be determined. This information in turn can give a detailed picture of the potential energies which govern the behavior of dissociating fragments, which in turn can be related to the behavior of the species in condensed (liquid or solid) phases. Such experimental spectroscopic studies of the photodissociation of polyatomic molecules are the goal of the current project.