Electron energy loss spectroscopic study of small molecules on transition metal surfaces

Citation

Wang, Youqi (1995) Electron energy loss spectroscopic study of small molecules on transition metal surfaces. Dissertation (Ph.D.), California Institute of Technology. doi:10.7907/h31m-na55. https://resolver.caltech.edu/CaltechETD:etd-10122007-112248

Abstract

The scheme of ultrahigh-resolution electron energy loss spectroscopy (UNREELS) is described in detail with graphical examples of the real data processing. On the basis of modern digital information processing techniques, this method promises to yield EEL spectra with the ultimate resolution and superior signal to noise ratio. The interaction of ammonia with clean and chemically modified Ru(001) surfaces were studied by using HREELS, TPD, and LEED techniques under UHV condition. Ammonia is found to interact with the surface chiefly through its lone-pair electrons, evidenced by the blue-shift of ammonia symmetric deformation mode and the increase of thermal desorption temperature of ammonia on both oxygen and nitrogen modified surfaces. No detectable dissociation of ammonia is found under the specified conditions. The reactions of gas-phase atomic hydrogen with oxygen and carbon monoxide pre-adsorbed on Ru(001) surface at low temperature were studied via HREELS technique. The experimental results can be understood via an Eley-Rideal-like mechanism. The decomposition mechanism of methylamine on Ru(001) surface was investigated by HREELS and TPD techniques. The cyanide adspecies was found to be side-on bonded on the ruthenium surface and its bond order is reduced from three to two.

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