Doctor of Philosophy (PhD)
Hard X-rays (2 KeV or greater) are used as spectroscopic tools in the characterization of chemical systems. X-ray absorption near edge structure (XANES) spectroscopy is used to characterize multiple groups of chemicals in a systematic fashion. This thesis focuses on chemical systems that in some context have geometrical constraints on their structure. They include self-assembled n-alkanethiol monolayers that are tethered to silver substrates, cyclic sulfides, and (Bis(diphenylphosphino) alkane tetracarbonyl metal complexes. The study of n-alkanethiol monolayers on Ag(111) contains the first observation in the literature of an anomalous resonance in the 18 carbon monolayer. A new interpretation of a subthreshold feature and spectra of improved quality versus previously published work are reported for cyclic polymethylene sulfides. X-ray reflectivity is used to make qualitative assessments of differences in the surface morphology of n-alkanethiol monolayers on silver substrates. The first inner shell excitation spectra of Bis(diphenylphosphino) alkane chromium complexes (alkane=methane, ethane, propane) are presented in addition to the first spectra of Bis(diphenylphosphino) ethane molybdenum and Bis(diphenylphosphino) ethane tungsten. All of these (Bis(diphenylphosphino) alkane tetracarbonyl metal complexes are examined in two ways, at both an inner shell orbital of the metal and at the phosphorus K-edge of the bridging ligand. These studies show that the inner shell X-ray spectra are sensitive to molecular geometry, bond angle, and molecular symmetry over a wide spectral range.
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Doomes, Edward Earl, "X-ray spectroscopy of geometrically constrained systems" (2002). LSU Doctoral Dissertations. 1668.
Erwin D. Poliakoff