Ion Mobility Studies of the Structures of Atomic Clusters

实验物理化学计划支持马丁·F·贾罗尔德继续进行研究，利用气相离子迁移率测量来确定中型星团的结构。在弱电场的影响下，气相离子通过缓冲气体的速度取决于其几何形状。尽管可以从迁移率中推断出有关几何图形的某些信息，但可以有多个几何图形具有相同的迁移率。因此，贾罗尔德提议将最近建造的高分辨率仪器与磁瓶负离子光电子能谱仪相结合。使用这种方法，将测量多达数百个原子的碳、硅和锗团簇的光电子光谱，作为几何和团簇大小的函数。原子团是含有几个到几千个原子的小块物质。由于各种原因，这些物种的物理和化学性质与散装材料的不同。研究这些性质并确定它们如何随星团大小的变化而变化，一直是过去十年来一项主要研究工作的目标。结构通常控制任何材料的物理和化学性质。因此，有关原子团簇几何结构的信息对于理解它们与尺寸有关的性质是至关重要的。这些研究将大大增加我们对4族(碳、硅和锗)元素簇的结构和成键的理解。

The Experimental Physical Chemistry Program support Martin F. Jarrold in his continuing studies to determine the structure of medium-sized clusters using gas phase ion mobility measurements. The speed with which a gas phase ion moves through a buffer gas under the influence of a weak electric field depends on its geometry. Although some information about the geometries can be deduced from the mobilities, more than one geometry can have the same mobility. Thus, Jarrold proposes to couple a recently-constructed high resolution apparatus with a magnetic-bottle anion photoelectron spectrometer. Using this approach, photoelectron spectra will be measured as a function of geometry and cluster size for carbon, silicon, and germanium clusters of up to hundreds of atoms. Atomic clusters are small pieces of material containing from a few to several thousand atoms. For a variety of reasons, the physical and chemical properties of these species are different than those of the bulk material. Examining the properties and determining how they change as a function of cluster size has been the object of a major research effort for the last ten years. Structure generally controls the physical and chemical properties of any material. Thus information about the geometric structure of atomic clusters is critical for understanding their size-dependent properties. These studies will substantially increase our understanding of the structure and bonding in clusters of the Group 4 (carbon, silicon and germanium) elements.