MIES-studies on size-selected clusters deposited on oxide surfaces

MIES 研究沉积在氧化物表面的选定尺寸团簇

• 批准号: 5404778
• 负责人: Professor Dr. Ulrich Heiz
• 金额: --
• 依托单位: Lehrstuhl für Physikalische Chemie
• 依托单位国家: 德国
• 项目类别: Priority Programmes
• 财政年份: 2003
• 资助国家: 德国
• 起止时间: 2002-12-31 至 2007-12-31
• 项目状态: 已结题
• 来源: https://gepris.dfg.de/gepris/projekt/5404778?language=en
• 关键词: MIES; studies; size; selected; clusters

This project aims to study the electronic structure of pure and ligated clusters on oxide surfaces by means of the metastable impact electron spectroscopy, MIES, in combination with the ultraviolet photoelectron spectroscopy, UPS, in order to understand their chemical properties. We focus in the first term of the project on well-defined metal clusters with well-known, different and specific chemical properties. The following systems will be investigated in detail spectroscopically: (a) Au3Sr, Au4 und Au8 supported on ultrathin MgO-films: In this example we first characterize the electronic states of the three clusters spectroscopically and compare the obtained results with existing ab initio calculations. Second, we study the binding behavior of 02 to these clusters and a possible activation of the adsorbant. These studies will give important information on the different chemical properties of the three clusters with respect to the oxidation of CO. (b) Pd-atoms supported on ultrathin Mg0-films: Here we study to what extent the oxidation of CO occurs via carbonate formation and/or coadsorption of CO and 02. In the first phase of the project a highly intense source for metastable He atoms will be built at the Technical University of Clausthal. This source will then be integrated into the analysis chamber of the existing cluster deposition experiment at the University of Ulm. In this experimental setup the hemispherical analyzer, necessary for the MIESS studies, is already available. In future these experiments will be extended to other systems. We will grow thin Ti02 and Si02 films onto Mo(110) and Mo(112), respectively, characterize existing defects of these surfaces and study the same cluster systems on these different support materials.

该项目旨在通过亚稳态碰撞电子能谱（MIES）结合紫外光电子能谱（UPS）研究氧化物表面上纯团簇和连接团簇的电子结构，以了解它们的化学性质。我们在项目的第一学期专注于定义明确的金属簇，具有众所周知的，不同的和特定的化学性质。下面的系统将详细研究光谱：（a）Au 3Sr，Au 4和Au 8支持在MgO薄膜：在这个例子中，我们首先表征的电子状态的三个集群光谱和比较所获得的结果与现有的从头计算。其次，我们研究了O2与这些簇的结合行为以及吸附剂的可能活化。这些研究将提供重要的信息，不同的化学性质的三个集群相对于CO的氧化。（B）Pd-原子上支持的Mg 0-薄膜：在这里，我们研究到什么程度的CO氧化发生通过碳酸盐形成和/或CO和02的共吸附。在该项目的第一阶段，将在克劳斯塔尔技术大学建造一个亚稳He原子的高强度源。然后，该源将被集成到乌尔姆大学现有的团簇沉积实验的分析室中。在这个实验装置的半球形分析仪，必要的MIESS研究，已经可用。将来，这些实验将扩展到其他系统。我们将分别在Mo（110）和Mo（112）上生长薄的TiO 2和SiO2膜，表征这些表面的现有缺陷，并研究这些不同载体材料上的相同簇系统。