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Theoretical Study for Dynamics of Molecules Near Metal Surfaces

金属表面附近分子动力学的理论研究

基本信息

批准号：
63540274
负责人：
OKIJI Ayao
金额：
$ 1.34万
依托单位：
Osaka University
依托单位国家：
日本
项目类别：
Grant-in-Aid for General Scientific Research (C)
财政年份：
1988
资助国家：
日本
起止时间：
1988 至 1990
项目状态：
已结题

项目摘要

The dynamical process of adsorbed atoms at surfaces is generally determined by the structure of the potential energy surface and the energy dissipation to the surface degrees of freedom. In the case of molecules having internal degrees of freedom such as rotation and vibration, those internal states undergo a change in the dynamical process at surfaces. Hence, the internal state excitation is also one of the main factors determining the dynamical process at surfaces. In this research, dynamical phenomena of molecules interacting with metal surfaces have been investigated from various viewpoints. 1. Friction coefficient of adatoms interacting with metal surfaces has been calculated with the aid of the Bethe Ansatz solution of the Anderson model. The many body effects on the friction coefficient have been clarified completely. 2. The energy dissipation of charged particles to the electronic system of metal surfaces has been investigated within the time-dependent Newns-Anderson model. The non-adiabatic effects have been clarified on the energy dissipation. 3. Thermal desorption spectra (TDS) of coadsorbed molecules have been calculated with the use of the Monte Carlo method for the lattice gas model. The effects of the pair interaction between adsorbed molecules on TDS have been clarified. 4. It has been found that characteristics of the potential energy surface, namely, the curvature of the reaction path, the height of the activation barrier and its position with respect to the curved region of the reaction path, influence strongly on the vibrational excitation of associatively desorbing hydrogen molecules and on the vibrationally assited sticking phenomenon. 5. Relationship between the reactivity of the surface and subsurface oxygen has been clarified through the investigation of the kinetic oscillation in the catalytic CO oxidation on Pd (110).

表面吸附原子的动力学过程一般由势能面的结构和表面自由度的能量耗散决定。在分子具有内部自由度的情况下，如旋转和振动，这些内部状态在表面的动态过程中经历变化。因此，内态激发也是决定表面动力学过程的主要因素之一。本研究从不同的角度研究了分子与金属表面相互作用的动力学现象。1.利用Anderson模型的Bethe Anatz解计算了吸附原子与金属表面相互作用的摩擦系数。对摩擦系数的多种体效应已完全阐明。2.在含时Newns-Anderson模型下，研究了带电粒子对金属表面电子系统的能量耗散。阐明了非绝热效应对能量耗散的影响。3.采用晶格气体模型的蒙特卡罗方法计算了共吸附分子的热脱附谱。阐明了吸附分子对相互作用对TDS的影响。4.研究发现，势能面的性质，即反应路径的曲率、活化势垒的高度及其相对于反应路径曲线区的位置，对缔合脱附氢分子的振动激发和振动协调粘连现象有很大的影响。5.通过对Pd(110)上CO催化氧化动力学振荡的研究，阐明了表面和亚表面氧的反应性之间的关系。