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Digitized Theses

Theses/Dissertations

1995

Physical

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Electronic Structure Of Gold-Silver Bimetallics, Arthur Bzowski Jan 1995

Electronic Structure Of Gold-Silver Bimetallics, Arthur Bzowski

Digitized Theses

The main thrust of this thesis concerns studies of the electronic structure of Au-Ag bimetallic materials, both in bulk alloys and in metallic overlayers on Ru(001). First, a series of bulk Au-Ag alloys: Au{dollar}\rm\sb{lcub}0.75{rcub}Ag\sb{lcub}0.25{rcub},\ Au\sb{lcub}0.67{rcub}Ag\sb{lcub}0.33{rcub},\ Au\sb{lcub}0.50{rcub}Ag\sb{lcub}0.50{rcub},\ Au\sb{lcub}0.25{rcub}Ag\sb{lcub}0.95{rcub},\ and\ Au\sb{lcub}0.05{rcub}Ag\sb{lcub}0.95{rcub}{dollar} has been studied using X-ray photoelectron spectroscopy (XPS), ultraviolet photoelectron spectroscopy (UPS), and X-ray absorption near-edge structure (XANES). It is found that in alloys with {dollar}>{dollar}50% atomic Au, the alloy d-band width narrows little relative to that of pure Au; however at 50% (and less) atomic Au concentration, the widths of the Au-Ag alloy d-band are much smaller than that …


The Growth And Magnetic Properties Of Metal Overlayer Systems: Palladium/Copper(100), Iron/Aluminum(100) And Iron/Sulfur/Gallium Arsenide(100), Geoffrey William Anderson Jan 1995

The Growth And Magnetic Properties Of Metal Overlayer Systems: Palladium/Copper(100), Iron/Aluminum(100) And Iron/Sulfur/Gallium Arsenide(100), Geoffrey William Anderson

Digitized Theses

Epitaxial growth of a metal overlayer on an appropriate substrate can be utilized to create systems which exhibit unique chemical and magnetic properties. This thesis will outline the investigation of three metal overlayer systems: Pd/Cu(100), Fe/Al(100) and Fe/S/GaAs(100). In the Pd/Cu(100) system the growth and evolution of defects were examined using re-emitted positron spectroscopy. Two changes in growth mode were observed: at 0.5 monolayer (representing the completion of the first alloy layer) and 1 monolayer Pd coverages (representing the start of bulk Pd growth). The bulk Pd film was observed to contain 1% vacancy-type defects. In the Fe/Al(100) system the …


New Porphyrins As Semiconductor Photosensitizers: Molecular Engineering For Solar Energy Conversion, Biswajit Choudhury Jan 1995

New Porphyrins As Semiconductor Photosensitizers: Molecular Engineering For Solar Energy Conversion, Biswajit Choudhury

Digitized Theses

The organizing properties of surface-active porphyrins can be employed to obtain large area, ordered arrays of electroactive organic molecules. The design, synthesis, and characterization of two families of surface active porphyrins, possessing variety of side chains, is described. These materials are solid at room temperature and exhibit well-behaved monomolecular films at an air-water interface.;In compressed monolayers, the porphyrin ring appears to be oriented so that the plane of the ring is perpendicular to the surface. The surface pressure-molecular area isotherms change with the length and nature of the side chains in a manner which suggests that a long side chain …


Intermolecular Forces And Statistical Mechanics Of Liquids, Maria Koulis Jan 1995

Intermolecular Forces And Statistical Mechanics Of Liquids, Maria Koulis

Digitized Theses

This research is involved with the construction of potential energy models for the interaction of closed shell atoms and/or molecules and with the study of the thermodynamic properties of pure liquids and liquid mixtures, through the use of statistical mechanical perturbation theory.;The previously developed Exchange-Coulomb potential energy model for the interaction of closed shell atoms is modified to correct its unphysical behaviour for small interspecies distances and so that it is applicable for interactions involving molecules. The new potential energy model is based on using the Heitler-London energy to represent the repulsive part, and a damped and overall corrected dispersion …


Circular Dichroism And Luminescence Studies Of Copper Binding To Metallothionein, Paul Anthony Presta Jan 1995

Circular Dichroism And Luminescence Studies Of Copper Binding To Metallothionein, Paul Anthony Presta

Digitized Theses

The metallothioneins (MT) are a class of low molecular weight, cysteine rich proteins found in almost all living things. The high sulfhydryl content imparts to these proteins the unique ability to bind a wide range of metals. The metallothioneins have been implicated in the storage and transport of essential metals, such as zinc and copper, and in the detoxification of toxic metals, such as cadmium. However, the exact physiological functions of these proteins remain a matter of speculation. In particular, little is known about the interactions of copper with MT. In this thesis, the structural and mechanistic properties of copper …


A New Photocatalytic Reactor For The Photodegradation Of Organic Contaminants In Water, Julio E. Valladares Jan 1995

A New Photocatalytic Reactor For The Photodegradation Of Organic Contaminants In Water, Julio E. Valladares

Digitized Theses

The {dollar}\rm TiO\sb2{dollar} photocatalytic degradation and mineralization of organic pollutants in water has been broadly demonstrated at the laboratory level for a wide number of organic pollutants. However, there are still some problems that need to be addressed in order to make this technology more practical. The design of heterogeneous photocatalytic reactor systems, still in the infancy of their development, is facing different problems such as light scattering, oxygen starving, particle separation and mass transfer. Additionally, there have also been a lack of a general method to evaluate the performance of the different reactor systems.;The present work addresses these problems …