Direct Observation of Internal Rotational Motion of Molecules Absorbed on a Surfaces

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On this research project, we have improved our experimental apparatus. The apparatus had been already enable to carried out the laser induced fluorescence experiments, and, after the present improvements, the laser ionization experiments could also be performed on this apparatus. Using this improved apparatus, we tried to observe adsorbed molecules, such as CO,CN, etc., on light metal surfaces, such as, Mg, Al, and Si, and we have succeeded to measure new spectra of some new molecular adsorbed systems. From the analysis of the observed spectra, we have obtained some new information on the internal rotational motion of the adsorbed species. The results of this project would provide useful guide to control of adsorbed molecules on the adsorbed surfaces.ApparatusAfter the improvements on our experimental apparatus executed by this research budget, it could perform the laser ionization experiments, which is higher sensitivity than the laser induced fluorescence method that we had, and using this new technique, we succeeded to observe new molecular adsorbed systems, because of the higher sensitivity.Experimental resultsWe succeeded to observe Si cluster systems, such as SiCCH, SiCN, and SiNC. It is found for the SiCN/SiNC system that the internal rotation motion of the CN species has quite complicated mechanism. For the Al and Ng systems, we analyzed some internal rotation motion potentials, and clearly showed that the potential has quite strong dependence upon the molecular adsorbed system. It was found that the 4th order anharmonic term is predominant for the potential of the MgOH system, and that the potential can be well described by the trigonometrical function for the MgNC/MgCN system.