|Budget Amount *help
¥1,900,000 (Direct Cost : ¥1,900,000)
Fiscal Year 1994 : ¥500,000 (Direct Cost : ¥500,000)
Fiscal Year 1993 : ¥500,000 (Direct Cost : ¥500,000)
Fiscal Year 1992 : ¥900,000 (Direct Cost : ¥900,000)
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
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