| Research Abstract |
Structures and reactivities of molecular systems interacting with naked metals, metal clusters, and metal surfaces are of much importance to investigate elementary processes of catalytic reactions on various surfaces. In this research project, we have studied several subjects of these topics by quantum mechanical methods. We make abstracts of these topics as follows.
1. Halogen chemisorption on an alkali-metal surface: Halogen chemisorption on an alkali metal surface involves 'hapooning', surface chemiluminescence, and surface electron emission. We investigate these phenomena by the DAM and the SAC/SAC-CI method. We found that the hapooning process and the surface chemiluminescence are one electron transfer processes between the bulk metal and Cl_2 through the highest-spin coupling mechanism. The surface electron emission is two electron process, one electron being transferred from the surface to Cl_2 and the other emitted out of the surface.
2. Chemisorption of H_2 on a ZrO_2 surface: O
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n a ZrO_2 surface, three types of H-H stretching and two types of Zr-H stretching have been observed by IR spectroscopy, suggesting that the three types of molecularly adsorbed sites and two types of dissociative adsorption exist on a ZrO_2 surface. The adsorption of H_2 on a ZrO_2 surface is investigated by using a cluster model with the Mudelung potential. We found two types of molecularly adsorbed hydrogen molecule and one type of dissociative adsorption.
3. Dative metal-metal bond: The nature of metal-metal bonds in the binuclear complexes (OC)_5Os-M(CO)_5 (M=W,Cr) is studied and compared with that of the covalent bonds in (OC)_5M-M(CO)_5 (M=Re,Mn). We confirm that the former complexes have a dative metal-metal bond, as suggested experimentally. The Os(CO)_5 fragment acts as an electron donor to the M(CO)_5 fragments.
4. Ground and excited states of metal complexes: The SAC/SAC-CI methods are applied to the calculations of the ground and excited states of RuO_4, OsO_4, and MnO^-_. The experimental spectra of these complexes are well reproduced by the present calculations. Less
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