Observation of surface reactions by a highly sensitive Raman spectroscopy

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We have carried out a Raman study to understand the mechanisms of various interesting phenomena concerning surfaces and interfaces. First we have constructed a highly sensitive Raman measurement system. Next we have carried out Raman measurements as follows.(1)We have found that the Raman spectra of graphitized mesophase spherules, heat treated at 2800ﾟC, show interesting change under intense laser irradiation. When they are irradiated with an intense laser beam, the width of the E2g band at 158Ocm^<-1> decreases while the intensity of the D band at 1350cm^<-1> increases, i.e. the correlation between these quantities is negative. We have also observed luminescence from graphitized mesophase spherules under intense laser irradiation. In order to interpret these phenomena, we suggest a model in which the bridge bounds between aromatic molecules in the graphitized mesophase spherules are broken by intense laser irradiation.(2)TiCI_3 is an important component of the Ziegler-Natta catalyst for the production of polyolefins. In order to clarify the mechanism of catalytic reactions, we have measured the Raman spectra of the alpha-TiCl_3 crystal as a first step. The observed spectra show five clear bands. By a normal mode analysis of the lattice vibrations, the five Raman bands can be assigned to three A_g modes, one E_g mode, and one combination mode A_g+E_g.