Polythiophenes have shown potential as inexpensive organic semiconductors because of their charge mobility properties. Small changes in structures can change the electronic and optical properties. Because oligothiophenes demonstrate the same electronic properties, have better solubility, and are easier to purify without defects, oligothiophenes are used as models for the polythiophenes. X-ray diffraction is an accepted method for studying the structure and arrangement of atoms in oligothiophenes; however, XRD requires crystalline solids for analysis. Obtaining suitable crystals can be difficult. In this paper, two crystallization techniques, vapor diffusion and zone sublimation, and the results are discussed. Raman spectroscopy, a type of vibrational spectroscopy, will give information about the structure of a molecule and can act as the molecular fingerprint of the molecule. Raman spectroscopy does not require crystalline solids and provides a relatively fast analysis. If the Willets lab can characterize the oligothiophenes by Raman spectroscopy, demonstrate distinguishable spectra for the different morphologies, and correlate this to the X-ray diffraction data, Raman spectroscopy will be an easier and faster means for analyzing the oligothiophenes. / text

published_or_final_version / Chemistry / Master / Master of Philosophy

published_or_final_version / Physics / Master / Master of Philosophy

published_or_final_version / Physics / Master / Master of Philosophy

No description available.

Quantitative multielemental analysis using Particle Induced X-ray Emission (PIXE) using 1 and 2 MeV proton bombardment on thin targets has been achieved. The method is based on the calculation of atomic ratios from experimentally determined relative x-ray efficiency curves. Sample preparation techniques involving digestion and homogenous deposition of samples and standards with a minimum of contamination have been investigated. The accuracy of the method has been evaluated using five standard reference materials obtained from the National Bureau of Standards. The elimination of bremsstrahlung associated with the charging effect of non-conducting samples in PIXE analysis has been accomplished using thin carbon foils in the beam path. Applications of the PIXE technique to studies on deep-sea ferromanganese nodules were performed. The utility of PIXE in the analysis of noduoles and in the following of the distribution of a large number of elements through the various stages of a processing scheme were demonstrated.

No description available.

The application and use of non-destructive portable x-ray fluorescence (XRF) analysis is a critical tool in the preservation and interpretation of cultural material. Portable XRF instrumentation produce elemental compositional data that is used to reconstruct current artifact composition, which can be related to materials and methods of manufacture, technological practice, as well as object condition and presence of corrosion surfaces. Portable XRF analysis is used to assess a variety of material classes utilized in artifact manufacture. The dissertation research is based on a series of three case studies that represent typical groups of material culture commonly encountered in conservation and conservation science research.Conservators and conservation scientists frequently undertake analysis and interpretation of disparate groups of materials. Often, these objects are tied together by research questions or themes directed by outside influences including preservation issues requiring action; curatorial research interests; museum exhibition programs; as well as many other cultural heritage stakeholders. To this end, both non-destructive and destructive tools that provide measurements of interest play critical roles in analysis. The case studies have been designed to answer common compositional questions relating to (a) bulk analysis of Chinese coins, (b) characterization of Southwestern ceramic colorants, and, (c) chemical examination of post-depositional manganese dioxide accretions occurring on archaeological ceramic materials. They evaluate the value of data produced using effectiveness of non-destructive portable XRF analysis for the interpretation of archaeological materials. The case studies provide a template for the development of conservation science research, predicated on object preservation, which produce meaningful data for the interpretation and conservation of the analyzed archaeological artifacts. Portable XRF provides useful data that is used to successfully interpret archaeological materials through (a) classification of metal alloys that can be related to published coin data, (b) identification of ceramic colorants and production technologies, and, (c) characterization of post-depositional product composition when used with established visual typologies.

Previous studies have attempted to probe the structure of ultra-thin Nickel silicide films as they evolve in the manufacturing process with limited success. These studies have used ultra-thin Nickel silicide films that were quenched during the manufacturer's annealing process at select temperatures. This study aims to determine the structure of quenched ultra-thin Ni-Si films using Grazing Incidence X-Ray Absorption Near Edge Spectroscopy (GI-XANES) and ab-initio calculations (FDMNES). Successful calculations were prepared for the δ and θ Ni2Si phases, as well as the Ni3Si2, NiSi and NiSi2 phases. The GI-XANES experimental data was taken at the Canadian Light Source, at the Hard X-Ray Microanalysis Beamline (HXMA). XANES and FDMNES are used to identify two phases of the ultra-thin films: the as-deposited phase as a low-ordered Ni3Si2 phase, and the epitaxial NiSi2 phase was found in samples annealed past 400˚C.

No description available.