Stereodynamics of Chemical Reactions on Solid Surfaces Induced by Molecules and Radicals

分子和自由基诱导的固体表面化学反应的立体动力学

基本信息

批准号：
17550011
负责人：
OKADA Michio
金额：
$ 2.4万
依托单位：
Osaka University
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (C)
财政年份：
2005
资助国家：
日本
起止时间：
2005 至 2007
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-17550011/
关键词：
Physics of Surfaces and Interfaces Atomic and Molecular Physics Catalytic and Chemical Processes

项目摘要

One of the ultimate goals of surface science is to be able to design surfaces with particular catalytic reactivity. This entails a need for an atomic-level understanding of the fundamental principles (elementary processes) underlying the bond-making and bond-breaking at surfaces. The orientation of a molecule incoming on the surface is expected to play an important role in such elementary processes. We have been developing a new machine of ultra-high-vacuum (UHV) compatible oriented-molecular beam line, in order to investigate for initial orientation-effect of an incoming molecule in the surface chemical reactions. The purpose of the present research project is to probe the surface-chemical reaction, especially on Si surfaces, in detail by controlling the molecular orientation of impinging molecules. We report results of a study on the incident-energy and the surface-temperature dependence of the steric effects in the dissociative adsorption of CH_3Cl on a Si(100) surface. The initial sticking probability of CH_3Cl on Si(100) was measured by the King-Wells method. Data presented show that the initial sticking probability for the Cl-end collision is larger at an incident energy of 120 meV than that in the CH_3-end collision. Furthermore, this steric preference is quite sensitive to the kinetic energy and the rotational state of CH_3Cl and the surface temperature. This study shows that the non-equilibrium surface trapping plays a key role in the initial step of the decomposition of CH_3Cl on Si(100). We also introduce the on-going experiments using another new apparatus equipped with the oriented-molecular beam line and the reaction chamber for X-ray photo-emission spectroscopy. In the reaction of oriented NO molecules with Si(111), we found that a N-end collision is more effective in the dissociative adsorption than O-end collision. In addition, we also elucidate the oxide-formation processes on Cu surfaces with oxygen molecular beam.

表面科学的最终目标之一是能够以特殊的催化反应性设计表面。这需要对原子级别的理解（基本过程）对债券建立和债券在表面上的基本原则（基本过程）的了解。在表面上输入的分子的方向有望在此类基本过程中起重要作用。我们一直在开发一台新机器，该机器是兼容定向的分子束系，以研究表面化学反应中传入分子的初始方向效应。本研究项目的目的是通过控制撞击分子的分子取向，详细介绍表面化学反应，尤其是在SI表面上。我们报告了一项关于入射 - 能量和空间效应的表面温度依赖性在CH_3CL对Si（100）表面解离吸附中的结果的结果。通过King-Wells方法测量了Si（100）上CH_3CL的初始粘性概率。提供的数据表明，在120 MeV的入射能量中，Cl-End碰撞的初始粘性概率比CH_3-端碰撞中的最初粘性概率更大。此外，该空间偏好对CH_3CL和表面温度的动能和旋转状态非常敏感。这项研究表明，非平衡表面捕获在CH_3CL在SI上分解的初始步骤中起关键作用（100）。我们还使用另一个配备有方向的分子梁系和X射线光发射光谱的反应室的新设备介绍了正在进行的实验。在定向的NO分子与Si的反应中（111），我们发现N端碰撞比O-End碰撞更有效。此外，我们还阐明了用氧分子束上的Cu表面上的氧化物形成过程。