A Theoretical Study on Electronic Transition of CO Adsorption on Platinum Pt(111) Surface

It is now technically possible for Raman spectroscopy to investigate in detail the catalytic reaction on the transition metal surfaces. However, there are only few theoretical papers reported on the contribution of the electronic excited states to the spectroscopic properties. During the interaction of the visible light with the transition metal surface, there exist a number of low-lying excited states due to the unfilled d orbital Nakai and Nakatsuji studied theoretically adsorbed CO on the Pt₂ cluster to simulate CO adsorbed on plartinum surfaces.¹ However it is known that the cluster with only two platinum atoms is insufficient to simulate CO adsorbed at surface. It is suggested in literature that a good simulated result generally needs to adopt a cluster with more than seven atoms. In this paper, we use a duster with 8 platinum atoms in the surface layer, which has been used by Kua and Goddard to mimic the oxidation of methanol on the Pt(111) surface.² Based on the interstitial electron model, they found that the cluster is the smallest and the best cluster possible to be used to mimic Pt(111) surface.