A Study on the Structure of Metastable Reaction Intermediates on Solid Surfaces and the Elementary Reaction Processes

我们发展了一种新的实验技术来研究亚稳态反应中间体在固体表面上的动力学行为。今天，真正需要对固体表面上的化学反应机理的基本理解，因为先进的材料技术，如分子束外延，有机金属化学气相沉积和X射线/带电粒子光刻，本质上是基于表面化学过程。新技术是利用由撞击电子的电子激发引起的离子解吸。电子激发后解吸的离子被称为携带丰富的信息的表面上的母体吸附分子的吸附状态。通过对解吸离子的详细分析，可以定量描述吸附物基态和激发态的势能面，我们研制了一种新型的飞行时间傅里叶变换离子谱仪（TOFFTIS），它在很低的能量下具有很高的探测效率和能量分辨率。TOFFTIS已安装在超高真空兼容2轴旋转组件上，并安装在真空室中。作为初步实验，我们研究了O ^+和CO ^+在CO/Ru（001）上的电子激发脱附。成功地获得了O ^+和CO ^+的平动能分布，表明TOFFTIS具有预期的性能。

We have developed a new experimental technique to investigate the dynamic behavior of the metastable reaction intermediates on solid surfaces. Today, the basic understanding of the mechanism of chemical reactions on solid surfaces is truly demanded, since the advanced material technology, such as molecular-beam epitaxy, organometallic chemical-vapor deposition and X-ray/charged-particle lithography, are based essentially on the surface chemical processes. The new technique is utilizing the desorption of ions induced by electronic excitations by impinging electrons. The ions desorbed upon electronic excitations are known to carry rich information about the adsorption state of the parent admolecules on the surface. Detailed analysis of desorbed ions will provide quantitative description of the potential energy surface, both of a ground state and excited states, of adsorbates.We have constructed a novel ion spectrometer, called time-of-flight Fourier-transform ion spectrometer (TOFFTIS), which has significantly high detection efficiency and high energy resolution at very low energies. The TOFFTIS has been mounted on an ultrahigh-vacuum Compatible 2-axis rotation assembly and installed in a ultrahigh vacuum chamber. As a preliminary experiment, electron-stimulated desorption of O^+ and CO^+ from CO/Ru(001) has been investigated. Translational energy distribution of O^+ and CO^+ has been successfully obtained, demonstrating that TOFFTIS has a performance as expected.