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Open Access Publications from the University of California

Electron Spectroscopy of Solid and Liquid Surfaces

  • Author(s): Langford, Joel
  • Advisor(s): Hemminger, John C
  • et al.
Abstract

During my time here at the University of California, Irvine, I spent my time on two separate, yet equal, projects; collecting photoelectron spectra of liquid solutions by utilizing a liquid jet approach, and studying the adsorption of gases onto metallic surfaces by high resolution electron energy loss spectroscopy (HREELS).

In total I studied four different aqueous systems using the liquid jet. The first four chapters of this dissertation are dedicated to each of those systems. The first chapter studies anatase titania nanoparticles suspended in a solution of aqueous nitric acid. The second chapter covers a comprehensive study of aqueous 1-propanol by liquid jet XPS and a comparison of the XPS data with molecular dynamic solutions. The third chapter explains an observed photoelectron intensity oscillation in aqueous solutions of 2,2,2-trichloroethanol, 2,2,2-trifluroethanol and 1-propanol. The concluding chapter on liquid jet XPS discusses the photoelectron spectroscopy of aqueous hexylamine, and the possible uptake of CO2 by hexylamine as measured by XPS.

The last chapter of this dissertation discusses H2S adsorption on W(100) as measured by HREELS. At temperatures of 160-170 K hydrogen sulfide on W(100) adsorbs as SH, and not in its molecular form. At room temperature H2S dissociates on the surface to form S and H atoms. Sulfur is thermally stable on the W(100) surface for temperatures of at least 1200 K. Annealing a sulfur saturated surface in a background of oxygen removes the surface of sulfur (presumably by SO2 formation and desorption). The same is also true for annealing an oxygen saturated W(100) surface in a background of H2S. A mode at 650 cm-1 is also discussed. Previous studies assumed this mode to be a bend of the SH group. However, I suggest this mode to either be a S-S stretch, or a sulfur stretch associated with a bridge bonded sulfur species.

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