Chemistry Commons^™

Photoelectron Imaging Of Iodide Centered Alkyl Halide Cluster Anions, Joshua S. Lasinski

All Theses and Dissertations (ETDs)

This dissertation presents results from cluster anion photodetachment experiments of the solvated iodide anion as a means of investigating electron molecule interaction. Due to the localization of the excess charge on the iodine atom, these experiments proceed analogously to electron scattering experiments, in that exposure to sufficient photon energy detaches the electron, which may or may not interact with the target molecule before being detected. Such interactions are related to temporary electron capture into the σ* orbital of the target molecule.

This dissertation begins with an analysis of the previously published I−·CH3X: X = I, Br, Cl) photodetachment results. These …

A Study On The Structure And Photodetachment Dynamics Of Copper Based Molecular Anions Using Photoelectron Spectroscopy, Nicholas Stephen Holtgrewe

Arts & Sciences Graduate Student Theses and Dissertations

This dissertation represents a study of the effects of electron molecule interactions in the detachment and dissociation dynamics of copper based molecular anions. Results are presented on the photodetachment of small copper oxide CuO_n⁻ (n = 1, 2) and copper fluoride CuF _n⁻ (n = 1, 2) molecular anions. Effects of different resonances are explored using the photoelectron angular distributions (PADs) and the relative intensity variations in vibrational channel cross sections. The specific resonances studied include dipole bound resonances, in which the electric dipole moment of the neutral molecule captures the outgoing electron, and electronic Feshbach resonances, …

Characterization Of Freshwater Natural Dissolved Organic Matter (Dom): Mechanistic Explanations For Protective Effects Against Metaltoxicity And Direct Effects On Organisms, Hassan A. Al-Reasi, Chris M. Wood, D. Scott Smith

Chemistry Faculty Publications

Dissolved organic matter (DOM) exerts direct and indirect influences on aquatic organisms. In order to better understand how DOM causes these effects, potentiometric titration was carried out for a wide range of autochthonous and terrigenous freshwater DOM isolates. The isolates were previously characterized by absorbance and fluorescence spectroscopy. Proton binding constants (pK_a) were grouped into three classes:acidic (pK_a ≤ 5), intermediate (5 < pK_a ≤ 8.5) and basic (pK_a > 8.5). Generally, the proton site densities (L_T) showed maximum peaks at the acidic and basic ends around pK_a values of 3.5 and 10, respectively. More …

Investigation Of Water-Molecule Complexes And Their Catalytic Effect On Important Atmospheric Reactions, Taylor Scott Cline

Theses and Dissertations

This dissertation is a collection of works that investigates issues related to environmental chemistry. The first portion of this research explores the role of water vapor on the kinetics of important atmospheric reactions. Work is presented on the self-reaction of β-hydroxyethyl peroxy radical (β-HEP) and the catalytic increase in reaction rate by water vapor. β-HEP serves as a model system for investigating the possible role of water vapor in perturbing the kinetics and product branching ratio of atmospheric reactions of other alkyl peroxy radicals. The self-reaction rate coefficient of β-HEP was investigated between 276-296 K with 1.0 × 10^15 to …

Identification Of An Active Site-Bound Nitrile Hydratase Intermediate Through Single Turnover Stopped-Flow Spectroscopy, Natalie Gumataotao, Misty L. Kuhn, Natalia Hajnas, Richard C. Holz

Chemistry Faculty Research and Publications

Stopped-flow kinetic data were obtained for the iron-type nitrile hydratase from Rhodococcus equi TG328-2 (ReNHase) using methacrylonitrile as the substrate. Multiple turnover experiments suggest a three-step kinetic model that allows for the reversible binding of substrate, the presence of an intermediate, and the formation of product. Microscopic rate constants determined from these data are in good agreement with steady state data confirming that the stopped-flow method used was appropriate for the reaction. Single turnover stopped-flow experiments were used to identify catalytic intermediates. These data were globally fit confirming a three-step kinetic model. Independent absorption spectra acquired between 0.005 …

Study And Identification Of Environmental Nanoparticles In Governors State University (Gsu's) Agricultural Fields, Ekta Desai

All Capstone Projects

Main purpose of this project is to study nanoparticles in Governors State University’s agricultural field and design experimental protocol for the same. Nanoparticles have one dimension that measures between 1 - 100 nanometers or less. Nanoparticles are widely used in day to day life such as in medicines, textiles, manufacturing and cosmetics. Due to their wide use, they can enter environment through many ways such as accidental spills during handling. Waste water treatment plant disposal serves as a main source of their entrance into the environment. Analysis of nanoparticles in environmental samples presents a number of challenges, including separation and …

Uv-Visible Microscope Spectrophotometric Polarization And Dichroism With Increased Discrimination Power In Forensic Analysis, Dale Kevin Purcell

All Open Access Legacy Dissertations and Capstone Projects

Microanalysis of transfer (Trace) evidence is the application of a microscope and microscopical techniques for the collection, observation, documentation, examination, identification, and discrimination of micrometer sized particles or domains. Microscope spectrophotometry is the union of microscopy and spectroscopy for microanalysis. Analytical microspectroscopy is the science of studying the emission, reflection, transmission, and absorption of electromagnetic radiation to determine the structure or chemical composition of microscopic-size materials. Microscope spectrophotometry instrument designs have evolved from monochromatic illumination which transmitted through the microscope and sample and then is detected by a photometer detector (photomultiplier tube) to systems in which broad-band (white light) illumination …

Gumbos And Nanogumbos: Applications As Photosensitizers In Dye-Sensitized Solar Cells, Atiya Nicole Jordan

LSU Doctoral Dissertations

Renewable energy is a major concern due to increased world energy consumption. In particular, solar energy is a type of renewable energy source that uses devices known as solar cells to convert sunlight to electricity. Specifically, devices referred to as dye-sensitized solar cells (DSSCs) employ dyes to absorb solar energy. Dyes derived from ruthenium complexes have been typically used in DSSCs. Unfortunately, several disadvantages are associated with current ruthenium complex photosensitizers, which can be attributed to limited supply and expense of metals, as well as reduced absorption in the near-infrared region of the electromagnetic spectrum. Accordingly, this dissertation is a …

Vibrational Spectroscopic Analysis Of Gunshot Residue : A Novel Approach For Detection And Characterization, Justin J. Bueno

Legacy Theses & Dissertations (2009 - 2024)

Due to the increasing prevalence of firearm related crimes, there is a need for an all-encompassing analytical technique which can rapidly detect and analyze trace crime scene firearm evidence. There are several forms of ballistics and trace evidence associated with firearm offenses. Historically, the most neglected piece of evidence has ironically been the most prevalent. Each firearm discharge produces a so called gunshot residue (GSR) sample, expelling dust and particles numbering from hundreds to thousands throughout the shooting environment. The detection of GSR at a crime scene or on a suspect is critical for determining what actually happened during a …

Raman Spectroscopic Analysis Of Body Fluids : Species Differentiation And The Effect Of Substrate Interference And Laser Power, Gregory Keith Mclaughlin

Legacy Theses & Dissertations (2009 - 2024)

Several recent discoveries demonstrate that Raman spectroscopy has a unique capability to characterize body fluid traces in a forensic capacity. This approach has thus garnered interest in the forensic community since 2008, when a proof of concept experiment established that blood, semen, vaginal fluid, sweat and saliva are easily differentiable through their Raman spectra. Several possible methods of identification have been described in the literature, one approach uses chemometrical models, and another applies recently formulated multidimensional Raman signatures. The analytical sampling method and the identification procedure provide several desirable traits for the field of forensic science. In particular, Raman spectroscopy …

Synthesis, Spectroscopic Characterization, And Genotoxicity Of A New Group Of Azo-Oxime Metal Chelates, Beyza Cabi̇r, Bariş Avar, Mehmet Gülcan, Ahmet Kayraldiz, Mükerrem Kurtoğlu

Turkish Journal of Chemistry

A new azo-oxime ligand, 2-[(E)-(hydroxyimino)methyl]-4-[(E)- (4-nitrophenyl)diazenyl]phenol, (pxoxH_2) (2), was prepared by condensation of hydroxylamminehydrochloride and 2-hydroxy5- [(4-nitrophenyl)diazenyl]benzaldehyde (1) with treatment of a solution of diazonium salt of p-nitroaniline and 2-hydroxybenzaldehyde in ethanol. The 6 coordination compounds, [Mn(pxoxH)_2(H_2O)_2].H_2O (3), [Co(pxoxH)_2(H_2O)_2].4H_2O (4), [Ni(pxoxH)_2(H_2O)_2].2H_2O (5), [Cu(pxoxH)_2].H_2O (6), [Zn(pxoxH)_2].6H_2O (7), and [Cd(pxoxH)_2(H_2O)_2].H_2O (8), were prepared by reacting Mn(II), Ni(II) Cu(II), Co(II), Zn(II), and Cd(II) ions with the ligand. The structures of the compounds were elucidated from the elemental analysis data and spectroscopic studies. The azo-oxime metal complexes were also characterized by XRD, magnetic moment, molar conductivity, and thermal analyses. Elemental analyses of the chelates …

Rat Brain Pro-Oxidant Effects Of Peripherally Administered 5 Nm Ceria 30 Days After Exposure, Sarita S. Hardas, Rukhsana Sultana, Govind Warrier, Mo Dan, Rebecca L. Florence, Peng Wu, Eric A. Grulke, Michael T. Tseng, Jason M. Unrine, Uschi M. Graham, Robert A. Yokel, D. Allan Butterfield

Chemistry Faculty Publications

The objective of this study was to determine the residual pro-or anti-oxidant effects in rat brain 30 days after systemic administration of a 5 nm citrate-stabilized ceria dispersion. A ∼4% aqueous ceria dispersion was iv-infused (0 or 85 mg/kg) into rats which were terminated 30 days later. Ceria concentration, localization, and chemical speciation in the brain was assessed by inductively coupled plasma mass spectrometry (ICP-MS), light and electron microscopy (EM), and electron energy loss spectroscopy (EELS), respectively. Pro- or anti-oxidant effects were evaluated by measuring levels of protein carbonyls (PC), 3-nitrotyrosine (3NT), and protein-bound-4-hydroxy-2-trans-nonenal (HNE) in the hippocampus, cortex, and …

Experimental And Theoretical Studies In Solid-State Nuclear Magnetic Resonance, Monica N. Kinde

Department of Chemistry: Dissertations, Theses, and Student Research

Solid-state nuclear magnetic resonance (SSNMR) has proven to be a powerful tool for probing molecular structure and dynamics. Deuterium SSNMR is particularly useful due to the presence of anisotropic interactions whose motional averaging contributes structural and dynamical insight. The magnitude and type of molecular motion can be determined from analysis of solid echo deuterium lineshapes and/or relaxation studies. This work uses various applications of solid-state NMR as well as ab initio and density functional computational methods to study three different areas of physical chemistry: biophysical chemistry, materials science and fundamental concepts of physical chemistry. The first project addressed the dynamics …

Synthesis And Applications Of Novel Silver Nanoparticle Structures, Kyle Dukes

All Theses

ABSTRACT
The field of nanotechnology is rapidly expanding across disciplines as each new development is realized. New exciting technologies are being driven by advances in the application of nanotechnology; including biochemical, optical, and semiconductors research. This thesis will focus on the use of silver nanoparticles as optical labels on cells, methods of forming different small structures of silver nanoparticles, as well as the use of silver nanoparticles in the development of a photovoltaic cell.
Silver nanoparticles have been modified with self-assembled monolayers of hydroxyl-terminated long chain thiols and encapsulated with a silica shell. The resulting core-shell nanoparticles were used as …

Monitoring Photocatalytic Degradation Of X-Ray Contrast Media With Raman Spectroscopy, Sabina Salkic

Masters Theses & Specialist Projects

X-ray contrast media such as diatrizoate and iohexol have been found in wastewater and drinking water and are difficult to remove because they are resistant to water treatment processes. A removal process can be started with ultraviolet photocatalytic degradation of X-ray contrast media in the presence of titanium dioxide or other catalysts. Raman spectra of diatrizoate and iohexol were taken in an aqueous solution in the presence and absence of titanium dioxide during exposure to ultraviolet radiation. Raman intensity is directly proportional to concentration; therefore, we can measure the rate of the reaction based on changes in the Raman spectrum. …

High Resolution Spectroscopy: The Study Of Isobutylene, Tabetha Lynn Osborn

Student Theses and Dissertations

The explosive bouquet theory suggests that canines trigger on volatile organic species within an explosive and not the pure explosive. Modeling an explosive detection scheme after this theory, an experimental design using mid infrared sources was established at the ArCLAS facility. A calibration program, documented within this thesis, was created in a Visual Basic platform as an Excel Add-In. The calibration program converts time based spectra collected with a germanium etalon into frequency spaced scans and then to known frequencies to allow spectral assignments to rovibrational transitions of molecules of interest. Additionally, the analysis of isobutylene, a volatile organic bouquet …

Novel Nonresonant And Resonant Mechanisms Leading To The Breakdown Of The Franck-Condon Approximation In Photoionization, David Adam Hardy

LSU Doctoral Dissertations

This thesis attempts to answer the question of how electrons interact with a molecular framework prior to and during emission through photoionization. These studies interrogate several behaviors of allowed and forbidden photoelectron transitions such as shape resonances, non-resonant intrachannel vibronic coupling as a result of Cooper minima, and chemically-induced nonresonant coupling, all of which provide new insights into correlations between the electronic and molecular degrees of freedom. Research presented in this thesis utilizes high-resolution photoelectron spectroscopy, and undulator-based synchrotron radiation at the Advanced Light Source, a synchrotron radiation source in Berkeley, California. Data are collected from near threshold to several …

Studies On A Dirhodium Tetraphosphine Hydroformylation Catalyst, Darina Polakova

LSU Doctoral Dissertations

The dirhodium tetraphosphine catalyst [Rh2(nbd)2(rac-et,ph-P4)](BF4)2 was investigated in acetone and water/acetone in order to explain better hydroformylation results in the latter solvent. In-situ NMR spectroscopy showed slower degradation in water/acetone. Less tendency to form penta/hexacarbonyl complexes in water/acetone was shown by 31P{1H} NMR and FT-IR. A pH decrease and hydroformylation studies in presence of a base indicated formation of a monocationic monohydride species. A new reaction mechanism was suggested that takes into account the observed differences from the acetone solvent system. The presence of water enabled production of hydride species when the dirhodium catalyst was exposed to CO gas. We …

Selective Multivariate Applications In Forensic Science, Caitlin Rinke

Electronic Theses and Dissertations

A 2009 report published by the National Research Council addressed the need for improvements in the field of forensic science. In the report emphasis was placed on the need for more rigorous scientific analysis within many forensic science disciplines and for established limitations and determination of error rates from statistical analysis. This research focused on multivariate statistical techniques for the analysis of spectral data obtained for multiple forensic applications which include samples from: automobile float glasses and paints, bones, metal transfers, ignitable liquids and fire debris, and organic compounds including explosives. The statistical techniques were used for two types of …

Identification Of Clay Minerals Of The Eastern Southern Region Of Lake Victoria By Ethylene Glycol And Heat: X-Ray Diffraction And Infrared Spectroscopy Studies, E. H. J. Lugwisha

Tanzania Journal of Science

The effect of glycol and heat on some clay minerals of the eastern southern region of Lake Victoria in Tanzania has been studied. First, Whole Rock Powder mount XRD analysis was carried out at the measuring range 2 # ranging between 2o – 65o. Four non-clay minerals found in samples were Na-feldspar, K-feldspar, pyrope and quartz. Oriented clay mineral XRD analysis diffractograms were developed when the air-dried samples were diffracted in measuring range 2# between 2oo – 32o. Main clay mineral groups found in the samples were kaolinite, illite and montmorillonite. After glycolating the samples, it was evident that kaolinite …

Spectroscopic Properties Of Lanthanide (Iii) Compounds In Aqueous And Ionic Media, Orissa A. Burghard, Sayandev Chatterjee, Zheming Wang, Samuel A. Bryan

STAR Program Research Presentations

Lanthanide containing materials are receiving increasing attention due to their wide range of potential applications including bioanalytical imaging, dye-sensitized solar cells, nano-biotechnology and catalysis. The unique spectroscopic properties (intense and sharp emission bands with high color purity and high quantum efficiency) of lanthanides make them strong candidates for use as bio-markers or selective detectors. The attractiveness of lanthanides as future imaging agents as well as recent interest in their potential use in biological media has increased the need to understand the behavior of lanthanides in the presence of other ions or in ionic media.

The complexity of the biological media …

Spectroscopic And Electronic Structure Studies Of Metalloenzyme Active Sites, Joseph Sempombe

Chemistry and Chemical Biology ETDs

This work reports on the electronic and geometric structural studies of xanthine oxidoreductase (XO), S-ribosylhomocysteinase (LuxS) and inducible nitric oxide synthase (iNOS) active sites resulting from the joint applications of electronic absorption, electron paramagnetic resonance and magnetic circular dichroism spectroscopic methods. XO catalyzes formal oxygen atom insertion into a substrate C-H bond, but differs from monooxygenase enzymes in that the inserted oxygen atom derives from metal activated water and reducing equivalents are generated rather than consumed. Studies on aldehyde inhibited' XO (a paramagnetic form observed during XO catalysis), analyzed in terms of the relationships between the g-, ^95,97Mo hyperfine, …

Testing And Optimization Of A Cavity Ringdown Laser Absorption Spectrometer, Michael Neal Sullivan

Student Theses and Dissertations

A new cavity rindgdown spectrometer has recently been assembled within the Arkansas Center for Laser Applications and Science (ArCLAS). In order to evaluate this new spectrometer, high resolution rovibrational and rovibronic spectra have been collected for a number of molecular species including oxygen and acetylene. These spectra have been analyzed and compared with corresponding data from the literature. During the instrumental evaluation process several overtone/combination bands of 13C₂H₂ were recorded in the 13,200-13,500 cm-1 region that currently appear to be missing from the literature. Forty-three lines have been assigned for the (tentatively assigned) 2ν₂ + 3ν …

Slow Magnetic Relaxation And Electron Delocalization In An S = 9/2 Iron(Ii/Iii) Complex With Two Crystallographically Inequivalent Iron Sites, Susanta Hazra, Sujit Sasmal, Michel Fleck, Fernande Grandjean, Moulay T. Sougrati, Meenakshi Ghosh, T. David Harris, Pierre Bonville, Gary J. Long, Sasankasekhar Mohanta

Chemistry Faculty Research & Creative Works

The magnetic, electronic, and Mössbauer spectral properties of Fe ₂L(µ-OAc)₂ClO₄, 1, where L is the dianion of the tetraimino-diphenolate macrocyclic ligand, H₂L, indicate that 1 is a class III mixed valence iron(II/III) complex with an electron that is fully delocalized between two crystallographically inequivalent iron sites to yield a [Fe₂]^V cationic configuration with a S_t 9/2 ground state. Fits of the dc magnetic susceptibility between 2 and 300K and of the isofield variable-temperature magnetization of 1 yield an isotropic magnetic exchange parameter, J, of -32(2) cm^-1 for an …

Studies On The Mechanism Of Phosphazene Ring-Opening Polymerization (Rop), Selen Bi̇lge

Turkish Journal of Chemistry

In this study, the ring-opening polymerization (ROP) of cyclic trimer N_3P_3Cl_6 catalyzed by [Et_3Si(N_3 P_3Cl_6)][CHB_{11}H_5Br_6] (3) obtained from the reaction of N_3P_3Cl_6 (1) and Et_3Si(CHB_{11}H_5Br_6) (2) at room temperature was investigated. This provided a unique opportunity to explore the polymerization mechanism. The coordinatively unsaturated cation [N_3P_3Cl_5]^+ is responsible for the ROP of N_3P_3Cl_6, and is formed by the intramolecular elimination of Et_3SiCl from 3. The detection of Et_3SiCl by ^1H-NMR as the catalysis proceeded offers new evidence for the formation of [N_3P_3Cl_5]^+. The progress of the catalysis was followed using ^{31} P-NMR and revealed the build-up of a polymer. Cyclic …

Structural Interactions And Dynamics Of Disease Related Proteins By Using Nmr Spectroscopy, Shadakshara Swamy Puttamadappa

Legacy Theses & Dissertations (2009 - 2024)

Nuclear Magnetic Resonance (NMR) is a powerful spectroscopic technique to study the structure, molecular interactions, and dynamics of proteins. Modern NMR instrumentation, advancements in experimental techniques and revolutionary developments in recombinant DNA technology have made NMR a versatile and very convenient tool for biomolecule characterization.

Non Aggregated Colloidal Silver Nanoparticles For Surface Enhanced Resonance Raman Spectroscopy, Aoife Power, John Cassidy, Tony Betts

Articles

Silver nanoparticles with a tuneable l max were produced as colloids by heterogeneous nucleation. The synthesis process is both fast and repeatable, producing stable PVA capped nanoparticles. The colloid’s effectiveness in the SERRS system was investigated using Rhodamine 6G, R6G, Crystal Violet, CV, and Malachite Green, MG, as probe molecules. A clear sensing trend was observed, where the Raman signal emitted was significantly enhanced by the addition of silver nanoparticles. A build up of signal intensity is observed until an optimum ratio is achieved, followed by a decline in signal intensity as the concentration of nanoparticles is further increased. The …

Speciation And Spectroscopy Of The Uranyl And Tetravalent Plutonium Nitrate Systems: Fundamental Studies And Applications To Used Fuel Reprocessing, Nicholas A. Smith

UNLV Theses, Dissertations, Professional Papers, and Capstones

This dissertation explores the use of UV-Visible spectroscopy and Time Resolved Laser Induced Fluorescence spectroscopy as near real time process monitors of uranium and plutonium concentrations in aqueous reprocessing trains. The molar absorptivities and linear ranges of these metals were investigated under total nitrate and acid concentrations similar to those found in current reprocessing systems. Concurrent to this, a new multiple wavelength monitor was derived that is capable of determining the total nitrate concentration spectroscopically. This method uses the uranium absorbance spectrum to calculate the nitrate concentration in solution. When used as part of an Advanced Safeguard suite, this technique …

Circular Dichroism Spectroscopy In The Undergraduate Curriculum, Adam R. Urbach

Chemistry Faculty Research

Circular dichroism spectropolarimetry (CD) is a method of optical spectroscopy that seems in most practical ways like UV−visible spectroscopy. The main difference between the two methods is that CD, instead of measuring the absorbance of light as a function of wavelength, measures the difference in absorbance of left versus right circularly polarized light as a function of wavelength. A CD spectrum is an observation of the structure of a chiral compound; it often serves as a “fingerprint” of the structure of biological molecules such as proteins and nucleic acids. For this reason, CD has been broadly applied in biochemistry and …

A Systematic Study Of The Effect Of Silver On The Chelation Of Formic Acid To A Titanium Precursor And The Resulting Effect On The Anatase To Rutile Transformation Of Tio2, Nicholas Nolan, Michael Seery, Steve Hinder, Linda Healy, Suresh Pillai

Articles

Anatase to rutile transition in an unmodified synthetic titania usually occurs at a temperature range of 600 – 700 °C. Various methods such as addition of metallic and non-metallic dopants and modifying the precursor have previously been reported to influence the anatase to rutile transition temperature. In the current study, the effect of addition of increasing amounts of silver to the extent of chelation of a formate group to a titanium precursor and the resulting effects on the transformation of anatase to rutile has been studied. The addition of silver (0, 1, 3 and 5 mol %) on the anatase …