Photodissociation Studies of Mass-Selected Solvated Cluster Ions

James M. Farrar，罗切斯特大学，支持 由实验物理化学计划拨款， 研究气相的光解离和碎裂 溶剂化金属阳离子。 要研究的例子包括 碱土金属离子被水、氨或 甲醇。 从这种类型的簇离子的研究，这是 在非常高的真空分子束条件下产生， 基本信息可以获得有关的性质 凝聚相环境中的离子分子相互作用。 在这些非常优雅的实验中，团簇离子 通过将低能金属离子注入到 溶剂分子从脉冲喷嘴的超音速流 源头 在质量选择之后，团簇离子是 被来自可调谐脉冲染料激光器的光解离，并且 子离子作为激光的函数被质量分析 波长 光学吸收光谱和产品质量 光谱用于阐明结构和动力学 溶剂化金属阳离子的性质。 在此过程中需要调查的具体问题 研究涉及：1）吸收光谱的变化， 簇大小的函数，2）溶剂分子的蒸发 作为一种能量耗散机制，以及3） 大团簇中分子内电子转移 的 实验将使用串联飞行时间进行 质谱仪，将在任期内建造 补助金

Dr. James M. Farrar, University of Rochester, is supported by a grant from the Experimental Physical Chemistry Program to study the photodissociation and fragmentation of gas phase solvated metal cations. The examples to be studied involve alkaline earth metal ions solvated by either water, ammonia or methanol. From studies of cluster ions of this type, which are produced under very high vacuum molecular beam conditions, much fundamental information can be obtained regarding the nature of ion molecule interactions in condensed phase environments. In these very elegant experiments, the cluster ions are produced by injection of low energy metal ions into a supersonic flow of solvent molecules from a pulsed nozzle source. Following mass selection, the cluster ions are dissociated by light from a tunable pulsed dye laser, and the daughter ions are mass analyzed as a function of the laser wavelength. Optical absorption spectra and product mass spectra are used to elucidate structural and dynamical properties of the solvated metal cations. Specific issues to be investigated during the course of this research involve: 1) changes in the absorption spectrum as a function of cluster size, 2) evaporation of solvent molecules as an energy dissipation mechanism, and 3) the possibility of intramolecular electron transfer in large clusters. The experiments will be performed using a tandem time of flight mass spectrometer which will be constructed during the term of the grant.