Theoretical Study for Dynamics of Molecules near Metal Surfaces

为了阐明分子在金属表面的反应性，需要建立与电子系统基态能量和激发态能量对应的势能面（PES）以及激发态弛豫机制的精确知识。从这个角度出发，对分子在金属表面的反应性进行了理论研究。1.通过对NO/Ag（111）双原子分子在金属表面散射动力学的计算结果与实验结果的比较，阐明了分子轴取向对散射动力学的影响。2.在分子从金属表面散射的分子内振动激发过程中，从电子系统到分子内振动自由度，即，非绝热效应起重要作用。3. C分子内振动的瞬态吸收差谱分析 ...更多信息 用超短脉冲激光在Pt（111）表面观察到的O的振动态，阐明了金属表面振动态的简谐性偏离和振动激发态的弛豫时间。4.从微观角度考虑了电子系统自由度与吸附物平移运动之间的耦合，提出了一种新的光刺激脱附模型。通过对脱附概率的模型计算与实验结果的比较，阐明了新模型的有效性。5. H_2/Cu体系中的解离吸附是活化过程的一个范例。旋转激发对解离吸附的影响有两种，转向效应和能量传递效应。前者在低转动能区占主导地位，后者在高能区占主导地位。其结果是，可以观察到的非单调依赖于旋转激励的粘附概率。少

In order to clarify the reactivity of molecules at metal surfaces, it is necessary to build up accurate knowledge of potential energy surfaces (PES) corresponding to the ground state energy and excited state energy of electron system, and relaxation mechanism of excited states. From this view, theoretical study has been done on the reactivity of molecules at metal surfaces. The obtained results are summarized as follows.1.On the basis of comparison between experimental and calculational results for scattering dynamics of diatomic molecules from metal surfaces, the dependence of PES on orientation of molecular axis has been clarfied for NO/Ag (111). 2. In the excitation process of intramolecular vibration in the scattering of molecules from metal surfaces, energy transfer from electron system to intramolecular vibrational degree of freedom, i.e., non-adiabatic effect plays an improtant role. 3. On the analysis of transient absorption difference spectra for intra-molecular vibration of C … More O on Pt (111) observed recently by the use of ultrashort-pulse laser, deviation of vibrational states from harmonicity and relaxation time of excited vibrational states at metal surfaces are clarified. 4. A new model is proposed for photo-stimulated desorption, in which the coupling between degrees of freedom of electron system and translational motion of adsorbates is taken into account from a microscopic viewpoint. On the basis of the comparison between model calculations and the experimental results for desorption probability, the validity of the proposed new model is clarified. 5. Dissociative adsorption in H2/Cu system is a paradigm of activated processes. There are two kinds of effects of rotational excitation on the dissociative adsorption, i.e., steering effect and energy transfer effect. The former is dominant for low rotational energy region and the latter for high energy region. As a result, non-monotonous dependendce of sticking probability on rotational excitation can be observed. Less