| Research Abstract |
The main purpose of this research is to clarify the nature of the single crystal surface which has different kinds of adsorption sites; i.e. step sites, kink sites and terrace sites. The prominent feature of this work is that all the experimentals were performed in situ condition, i.e. in electrochemical cells, and this is quite important for the elusidation of catalysis and electrochemistry in the atomic-scale point of view.
At first, overlayer structures of CO adsorbed on several single crystal surfaces, Pt(111), (110), (100), (11 1 1) and (711), have been investigated by infrared reflection absorption spectroscopy. There exist at least four kinds of adsorption bands of CO on these electrode surfaces, i.e. on-top CO on stepped and terrace atoms, symmetric and asymmetric bridge CO at around 2045, 2060, 1880 and 1910 cm^<-1>, respectively. By changing the applied potental, surface coverages and detection time scale, the characteristic behavior of the band intensities as well as their frequencies of these IR bands were observed.
Second theme of this work was the elucidation of detailed mechanism of surface enhanced Raman scattering effect. To enhance the Raman signals of adsorbed species, atomic scale roughness is the determining factor. In this research, the roughness has been known to be the metal clusters consisted of several atoms. The electronic states of the culster must affect the enhancement of SERS.
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