Physical Chemistry Commons^™

Accelerated Broadband Spectra And Attosecond Charge Migration Simulations Using Real-Time Time-Dependent Density Functional Theory, Adam S. Bruner

LSU Doctoral Dissertations

In this dissertation, the calculations of light-matter interactions offer insight into the structure and dynamical response of electrons in molecular systems. Such information is useful for characterizing molecules, electronic structure, photochemistry, photomaterials, and a host of other applications. In the first part of this work, simulations of broadband absorption spectra are accelerated by the use of Pad´e approximanants of Fourier Transforms and dipole decomposition. Electronic absorption spectra from valence and core levels are obtained using time-dependent methods and compared to results from established perturbative techniques. In addition, core level absorption spectra are calculated for a nickel porphyrin and shown to …

Investigation Of Structure And Dynamics Of Deep Eutectic Solvent Using Infrared Spectroscopy, Yaowen Cui

LSU Doctoral Dissertations

Deep Eutectic Solvents (DES) are liquid mixtures prepared from solids. As a new class of green solvents, DES not only share many properties with ionic liquids, such as low volatility, conductivity, tailorable constituents, but also have some advantages over ionic liquids, like easier preparation, safe and inexpensive materials, biodegradability, low toxicity, and excellent solubility. Because of those attractive properties, DES has been studied in many scientific and engineering fields. However, compared with the great number of studies of the application, many questions about structure and dynamics of DES are unanswered. To shed light on the mystery of solvent or solvation …

Investigation On The Dissociative Photoionization Mechanism Of Furfural, Investigation Of The Absolute Photoionization Cross Sections Of Three Potential Propargylic Fuels, And Ab Initio Analysis On Potential Superbases Of Several Hyperlithiated Species: Li3f2o And Li3f2(Oh)N (N = 1, 2, 3), Matthew Winfough

Master's Theses

This thesis presents the study photoionization cross sections of three different propargylic biofuels; dipropargyl ether, propargyl alcohol, and propargylamine, in chlorine radical-initiated combustion experiments at the Chemical Dynamics Beamline (9.0.2) at the Advanced Light Source of the Ernest Orlando Berkeley National Laboratory in Berkeley, California. Additionally, the unimolecular dissociative photoionization mechanism of furfural was studied using photoelectron photoionization coincidence (PEPICO) spectroscopy at the vacuum ultraviolet beamline at the Swiss Light Source of the Paul Scherrer Institut in Villigen, Switzerland. Dissociation products and mechanisms for furfural were identified over a photon energy range of 10.9 to 14.5 eV. Lastly, a study …

Multi-Reference Systems In Chemistry; Unconventional Bonding In Organic Chemistry; Covalent Bonding In Transition Metal Clusters, Alan Wilfred Humason

Chemistry Theses and Dissertations

The geometries, chemical properties, and reactivities of molecules are determined by their electronic structure. The field of ab initio computational chemistry works to calculate the kinetic and potential energies between the nuclei and electrons of a molecule. These calculations usually begin with the determination the electronic ground state.

Molecules that cannot be adequately described with a single, ground state configuration are called \textit{multi-reference systems}, which require the calculation of a linear combination of all pertinent electronic configurations, with a corresponding increase in computational cost. This is not `black box' methodology, because solving these systems requires a good understanding of the …

Advances In Local Vibrational Mode Theory And Unified Reaction Valley Approach (Urva), Yunwen Tao

Chemistry Theses and Dissertations

Since the establishment of the Local Vibrational Mode Theory and the Unified Reaction Valley Approach (URVA), these two research pillars have been pushed forward in the CATCO group and played an important role in (i) characterizing the chemical bonds in molecules and (ii) molecular chemical reactions. This dissertation elaborates my contributions to the Local Vibrational Mode Theory and the Unified Reaction Valley Approach (URVA).

We have applied the Local Vibrational Mode Theory to hydrogen bonding in liquid water and proposed an explanation for the Mpemba effect. We explored and discovered new directions of applying local vibrational modes majorly in characterizing …

Detection Of Salen-Type Tracers For Subterranean Fluid Flow Monitoring Using Surface-Enhanced Raman Spectroscopy, Jenny C. Sanchez

Chemistry and Chemical Biology ETDs

A series of hydrocarbon and aqueous soluble salen-type ligands have been synthesized and characterized by electronic and vibrational spectroscopy. Aqueous soluble salen-type ligands were complexed to a metal and investigated as potential underground fluid flow tracers using Surface-Enhanced Raman Spectroscopy (SERS) as the analytical technique. Vibrational spectra obtained from SERS was shown to have enhanced the spectral signal for these complexes in low concentrations though did not show significant differences between the free ligands and their metal complexes. This research has shown that, with some structural modifications, salen-type ligands can be effective candidates as subterranean fluid flow tracers when SERS …

A Detailed Study Of Novel High-Performance Bromine And Phosphorus Based Reactive Flame Retardants In High-Quality Bio-Polyol Based Rigid Polyurethane Foams, Sanket Bhoyate

Electronic Theses & Dissertations

Structural fire is one of the most catastrophic issues related to human safety observed from reports of National Fire Protection Association of United States in past years. Polyurethanes are one of the important structural material used as thermal insulation in housing. They are also used in automotive, construction, medical, packaging, furniture, thermal, electrical, and vibration insulation. Considering this, we have synthesized bio-based polyurethane foams using limonene-based polyol, isocyanates, and other compounds. Flame retardancy was imparted using reactive flame retardant polyols. Firstly, flame retardancy test was performed on the foams using two novel aliphatic and two novel aromatic bromine-based synthesized reactive …

Nanocomposites Of Polypyrrole And Cobalt Oxide As Efficient And Stable Multifunctional Materials For Supercapacitors And Overall Water Splitting, Ahlam Alghamdi

Electronic Theses & Dissertations

NANOCOMPOSITES OF POLYPYRROLE AND COBALT OXIDE AS EFFICIENT AND STABLE MULTIFUNCTIONAL MATERIALS FOR SUPERCAPACITORS AND OVERALL WATER SPLITTING

An Abstract of the Thesis by

Ahlam Alghamdi

The main objective of this study is to synthesize nanostructured cobalt oxide decorated on polypyrrole using a facile method for energy applications. For this, polypyrrole was first synthesized using a chemical polymerization method. In the second step, a varying amount of cobalt oxide was decorated on polypyrrole using a hydrothermal process. The synthesized materials were structurally and electrochemically characterized. It was observed that the electrochemical properties of the composites depend on their composition. The …

Methylglyoxal Uptake Coefficients On Aqueous Aerosol Surfaces, David O. De Haan, Natalie G. Jimenez, Alexia De Loera, Mathieu Cazaunau, Aline Gratien, Edouard Pangui, Jean-Francois Doussin

Chemistry and Biochemistry: Faculty Scholarship

In order to predict the amount of secondary organic aerosol formed by heterogeneous processing of methylglyoxal, uptake coefficients (γ) and estimates of uptake reversibility are needed. Here, uptake coefficients are extracted from chamber studies involving ammonium sulfate and glycine seed aerosol at high relative humidity (RH ≥ 72%). Methylglyoxal uptake coefficients on prereacted glycine aerosol particles had a strong dependence on RH, increasing from γ = 0.4 × 10–3 to 5.7 × 10–3 between 72 and 99% RH. Continuous methylglyoxal losses were also observed in the presence of aqueous ammonium sulfate at 95% RH (γAS,wet = 3.7 ± 0.8 × …

Photoelectrochemical Studies On Non-Noble Metal Based Catalysts Towards Tandem Solar Water Splitting, Arun Siddarth Sridhar

Dissertations

Photoelectrochemical (PEC) water splitting makes direct use of solar energy incident on semiconductor photoelectrodes, and it is a convenient, economic option to produce high purity hydrogen at low temperatures. The use of multiple light absorbers can increase overall solar energy utilization and provide a solution to the trade-off between overall band gap and band edge positioning of photoelectrodes specific to solar water oxidation and water reduction. The study of non-noble metal based catalysts for hydrogen evolution reaction (HER) and oxygen evolution reactions (OER) are essential for economic practical commercialization of photo-electrolyzers. This dissertation focuses on the use of a variety …

Computational Modeling Of Electronically Excited States In Cobalamin-Dependent Reactions., Brady D. Garabato

Electronic Theses and Dissertations

The current understanding of the photolytic properties of Vitamin B12 derivatives or cobalamins are summarized from a computational point of view. The focus is on two non-alkylcobalamins, cyanocobalamin (CNCbl) and hydroxocobalamin (HOCbl), two alkylcobalamins, methylcobalamin (MeCbl) and adenosylcobalamin (AdoCbl), as well as the stable cob(II)alamin radical. Photolysis of alkylcobalamins involves low-lying singlet excited states where photo-dissociation of the Co-C bond forms singlet-born alkyl/cob(II)alamin radical pairs (RPs). Potential energy surfaces (PESs) of low-lying excited states as functions of both axial bonds provide the most reliable tool for analysis of photochemical and photophysical properties. Due to the size limitations associated with the …

Singlet Oxygen Oxidation Of Guanine, 9-Methylguanine And Guanine-Cytosine Base Pair: Dynamics And Kinetics Revealed By Parallel Gas- And Solution-Phase Experiments And Computations, Wenchao Lu

Dissertations, Theses, and Capstone Projects

Singlet oxygen (¹O₂) oxidatively generated damage of DNA gives rise to mutagenesis, carcinogenesis, and cellular death. Guanine is the most susceptible DNA target of ¹O₂. The related process has been studied over three decades but the mechanism has remained elusive. My thesis research has focused on reaction mechanism, dynamics and kinetics of ¹O₂ oxidation of guanine, 9-methylguanine and guanine-cytosine base pair, from the gas-phase bare ions, through hydrated clusters, to aqueous solution. Various techniques have been adapted in the work, including ¹O₂ generation and detection, guided-ion beam tandem mass …

Computational Study Of Lawesson’S Reagent Mediated Fluorenone Dimerization Forming 9,9’-Bifluorenylidene, Andrew Jourdan Eckelmann

Graduate Theses/Dissertations

The ambition of this work is to start a path to the a priori rational design of high yield production for electron acceptors with finely tuned band gaps, from the comfort of an armchair. To this end, organic photovoltaics offer a cheap and sustainable means of manufacture using readily available materials and avoids the toxicity of some of the heavy metals used in first and second-generation solar cells such as cadmium. The microwave assisted Lawesson’s reagent mediated one-pot one-step solventless synthesis takes less than 3 minutes and results in an 84% yield of 9,9’-bifluorenylidene from two equivalents of fluorenone. While …

Errata For Manuscript #34, Carl W. David, Jan Siroky

Chemistry Education Materials

An error in manuscript 34 of this collection concerning the Laplacian in spherical polar coordinates is corrected.

A Label-Free Immunosensor Based On K3[Fe(Cn)6] And Aldehyde-Functionalized Pyridinium, Xia Hu, You-Ming Shen, Guang-Yu Shen

Journal of Electrochemistry

A novel aldehyde-functionalized pyridinium was successfully synthesized. Using K₃[Fe(CN)₆] as a redox species modified on the surface of the electrode through Poly(diallyldimethylammonium chloride), we developed a label-free immunosensor based on aldehyde-functionalized pyridinium that was applied to simplify antibody immobilization on the electrode surface, in which no additional chemical cross-linking was required. In addition, the introduction of K₃[Fe(CN)₆] on the surface of electrode avoided the use of other redox species in the electrolyte solution. Under the optimal experimental conditions, differential pulse voltammetry (DPV) signals corresponding to different α-Fetoprotein (AFP) concentrations were measured. After …

One-Step Co-Deposition Of Zsm-5/Pani/Pss Electroactive Film And Its Kinetics Characteristics Of Electrochemical Control Selective Separation For Pb2+ Ions, Wen-Lei Qiao, Xiao Du, Feng-Feng Gao, Jun-Lan Zheng, Sha-Sha Li, Xiao-Gang Hao

Journal of Electrochemistry

A novel electroactive composite film consisting of ZSM-5/polyaniline/polystyrene sulfonate(ZSM-5/PANI/PSS) was prepared by double pulse one step co-deposition method. The ZSM-5/PANI/PSS composite film was characterized by FT-IR, SEM, XRD, and XPS techniques. The highly crystalline nano-ZSM-5 was synthesized by hydrothermal method, which could be evenly dispersed in aqueous solution by ultrasonic treatment. The synthesis condition of composite film was optimized through changing the pH value of solution. The ZSM-5/PANI/PSS composite film showed higher adsorption capacity for Pb²⁺ ions. Langmuir model was applied to analyze the adsorption process. The adsorption capacity of composite film for Pb²⁺ ions was 235 mg·g …

Synthesis And Electrochemical Properties Of Li3V2(Bo3)3/C Anode Materials For Lithium-Ion Batteries, You Wang, Yi-Wen Zeng, Xing Zhong, Xing Liu, Quan Tang

Journal of Electrochemistry

The Li₃V₂(BO₃)₃/C (LVB/C) composite materials were successfully synthesized in two steps:Firstly, a stoichiomertric mixture of Li₂C₂O₄, V₂O₅, H₃BO₃, H₂C₂O₄•H₂O and ethanol was thoroughly ball-milled to get the precursors. Secondly, the precursors were post-calcinated to get the ultimate products. The calcination temperatures of 750 ℃, 800 ℃ and 850 ℃ were selected based on TG-DTA analyses. The crystal structures, surface morphologies and carbon contents of the samples calcinated at five conditions, …

Electrochemical Performance Of Moo2-C Composite Coatings, Quan-Yi Li, Qi Yang, Yan-Hong Zhao

Journal of Electrochemistry

The molybdenum dioxide-carbon(MoO₂-C)composite coatings on the surface of Cu foils were prepared by simple knife coating route and followed by sintering in vacuum. The morphology, composition, structure and electrochemical performance of the MoO₂-C composite coatings were investigated. The results demonstrated that the MoO₂-C composite coatings consist of MoO₂ nano-particles with monoclinic crystal structure and amorphous carbon. Some MoO₂ nano-particles with a size range of 5-30nm were loaded on the surface of carbon matrices; while some MoO₂ nano-particles with a size of ~5nm were encapsulated inside. The composite coatings showed porous structure …

Preparation Of Ni(Dpim)2Cl2 Complex For The Electrocatalytic Reduction Of Co2, Li-Pu Zhang, Dong-Fang Niu, Xin-Sheng Zhang

Journal of Electrochemistry

A new Ni(dpim)₂Cl₂complex using 2-(diphenylphosphino)-1-methylimidazole (dpim) as ligand was prepared and served as a catalyst for the electrochemical reduction of CO₂. The electrochemical redox behavior of Ni(dpim)₂Cl₂ in CH₃CN/TPABF₄ solution under nitrogen atmosphere showed the two-electron irreversible reduction at -0.7 V and one-electron quasi-reversible reduction at -1.3 V. After bubbling CO₂ into the electrolyte, the reduction peak appeared at -1.3 V became irreversible and the peak current increased from 0.48 mA·cm^-2 to 0.55 mA·cm^-2. Moreover, the peak current at -1.3 V could further increase …

Preparation Of Co3O4/Ti Electrocatalytic Membrane Electrode For Catalytic Oxidation Of Benzyl Alcohol, Yu-Mei Zheng, Zhen Yin, Hong Wang, Jian-Xin Li

Journal of Electrochemistry

The cobalt oxide(Co₃O₄) nanoparticles were loaded on microporous Ti membrane to prepare Co₃O₄/Ti electrocatalytic membrane electrode by dip-coating method. The microstructures and electrochemical properties of Co₃O₄/Ti electrocatalytic membrane were investigated. The Co₃O₄/Ti electrocatalytic membrane reactor (ECMR) assembled by using the Co₃O₄/Ti electrocatalytic membrane as an anode was adopted for catalytic oxidation of benzyl alcohol to produce benzaldehyde and benzoic acid.The effects of different operation parameters on benzyl alcohol conversion, and selectivity to benzaldehyde and benzoic acid of ECMR were studied. …