Molecular Organic Photovoltaic Cells And Applications,
2023
Saint John's University, Jamaica New York
Molecular Organic Photovoltaic Cells And Applications, Julie Liu
Theses and Dissertations
The absorption, light scattering, and anti-Stoke’s fluorescence of chlorophyll and closely related sodium copper chlorophyllin were examined in various solutions with a wide range of refractive index and permittivity. It was evident that radiative photo electron decay corresponded to low permittivity solvents, but not to solvent refractive index. Additionally, non-radiative decay was dominant in high permittivity solvents. The properties suggest evolution has provided plants with an ability to redirect light to the chlorophyll in the high permittivity (water) photosynthesis center. Exploratory solar cells exploiting lifetime switching were developed and tested, wherein strong photovoltaic response was exhibited, along with the unique …
Exploration Of Electron Dynamics In A Strong Field By Time Dependent Configuration Interaction With A Complex Absorbing Potential,
2023
Wayne State University
Exploration Of Electron Dynamics In A Strong Field By Time Dependent Configuration Interaction With A Complex Absorbing Potential, Paul Hoerner
Wayne State University Dissertations
Strong field electron dynamics are a quickly developing field of study in physical chemistry. In order to better understand experimental observations, there is a need for computational tools to simulate electron dynamics in a strong field. Due to the nature of strong electric fields, this requires the solving of the time dependent Schrödinger equation (TDSE). Various methods have been used to solve the TDSE in a strong field. In order to look at molecular systems while accurately treating the underlying physics, a method that balances computational affordability with theoretical rigor is necessary. The chosen method that matches these criteria is …
High Order Structures Formed By The Natural Aromatic Amino Acids,
2023
University of Arkansas, Fayetteville
High Order Structures Formed By The Natural Aromatic Amino Acids, Gabriel Alexander Kupovics, Zeina Alraawi
Inquiry: The University of Arkansas Undergraduate Research Journal
Excessive concentrations of the natural aromatic amino acids phenylalanine and tyrosine are characteristic of the severe genetic abnormalities known as phenylketonuria (PKU) and tyrosinemia, respectively. Within this context, this feature article authenticates claims that tryptophan can form amyloid-like supramolecular structures in vitro and is the first to propose potential mechanisms of tryptophan self-assembly, including hydrophobic and electrostatic interactions. Thioflavin T (ThT) fluorescence kinetics and transmission electron microscopy (TEM) data suggest the formation of amyloid-like fibrillar structures by natural aromatic amino acids in vitro. Additionally, the propensity of amino acid aggregation increases in the presence of sodium dodecyl sulfate (SDS). The …
Vanadium Partitioning Between Magnetite, Hematite, And A Hydrothermal Fluid: Implications For Iocg And Ioa Deposits,
2023
Northern Illinois University
Vanadium Partitioning Between Magnetite, Hematite, And A Hydrothermal Fluid: Implications For Iocg And Ioa Deposits, Jeremy Raymond Nederbo
Graduate Research Theses & Dissertations
Iron oxide-copper-gold (IOCG) and iron oxide-apatite (IOA) deposits are major sources of iron contained within magnetite and/or hematite as well as copper contained within copper-iron sulfides and gold as a native metal. Their formations have been attributed to magmatic, hydrothermal, or a mixture of magmatic-hydrothermal processes. Vanadium can readily substitute into magnetite via ion exchange due to similar atomic radii and charges as iron and has thus been hypothesized to be an effective tracer of hydrothermal or magmatic inputs. To evaluate the mobility of vanadium in a magnetite-hematite-fluid system, experiments on the partitioning of vanadium between magnetite, hematite and a …
Investigation Of Ch4 Adsorption And Activation On Modified Metalloporphyrin Graphene Sheets,
2023
Eastern Illinois University
Investigation Of Ch4 Adsorption And Activation On Modified Metalloporphyrin Graphene Sheets, Brianna Haase
Masters Theses
Finding a good catalyst for C-H bond breaking is important due to the rise of natural gas and crude oil emissions. From 2000-2006, CH4 emission concentrations stabilized, but in 2007, it sharply started increasing again. For example, atmospheric CH4 levels were 1886.37 ppb in July 2021 but this rose to 1904.52 ppb in just one year. Precious metal catalysts, such as Ir systems, have been used for C-H bond breaking, but are not sustainability ideal as they are costly to produce and have a significant carbon footprint. Because of this, less expensive 3d metal catalysts have risen in investigative …
Using Superatomic Clusters And Charge Transfer Ligands To Control Electronic Characteristics Of Phosphorene Nanoribbons And Phosphorene Monolayer,
2023
Virginia Commonwealth University
Using Superatomic Clusters And Charge Transfer Ligands To Control Electronic Characteristics Of Phosphorene Nanoribbons And Phosphorene Monolayer, Ryan Lambert
Theses and Dissertations
Phosphorene is a two-dimensional electron poor p-type semiconductor with high carrier mobility and great promise for applications in electronics and optoelectronics. As the main theme in this dissertation, the following work represents different investigations of various electronic properties associated with phosphorene. Most notable are the findings on charge transfer doping with metal-chalcogenide superatoms which displays novel control of the two most important properties of a semiconductor – the band gap energy and the nature of carriers. By tuning the width of the gap and p-/n-type character of conduction, we gain control over a material’s capacity to play a certain role …
Rovibrational States Calculations Of The H2o-Hcn Heterodimer With The Multiconfiguration Time Dependent Hartree Method,
2023
Missouri University of Science and Technology
Rovibrational States Calculations Of The H2o-Hcn Heterodimer With The Multiconfiguration Time Dependent Hartree Method, Hervé Tajouo Tela, Ernesto Quintas-Sánchez, Marie Lise Dubernet, Yohann Scribano, Richard Dawes, Fabien Gatti, Steve Ndengué
Chemistry Faculty Research & Creative Works
Water and hydrogen cyanide are two of the most common species in space and the atmosphere with the ability of binding to form dimers such as H2O-HCN. In the literature, while calculations characterizing various properties of the H2O-HCN cluster (equilibrium distance, vibrational frequencies and rotational constants) have been done in the past, extensive calculations of the rovibrational states of this system using a reliable quantum dynamical approach have yet to be reported. In this work, we intend to mend that by performing the first calculation of the rovibrational states of the H2O-HCN van der …
Hyperpolarized Nitrogen-15 Mri Contrast Agents For Hypoxia Sensing Via Reversible Exchange With Parahydrogen,
2023
Wayne State University
Hyperpolarized Nitrogen-15 Mri Contrast Agents For Hypoxia Sensing Via Reversible Exchange With Parahydrogen, Mohammad Shah Hafez Kabir
Wayne State University Dissertations
The detection of hypoxia in hypoxic-related diseases can provide crucial information for treatment planning and assessment of therapy response. Although Positron Emission Tomography (PET) was employed as a research tool for imaging of hypoxia detection, it has several limitations. Our motivation is to develop a hyperpolarized (HP) molecular probe for hypoxia sensing. My dissertation presents the utility of Signal Amplification By Reversible Exchange in SHield Enables Alignment Transfer to Heteronuclei (SABRE-SHEATH) to hyperpolarize a wide range of N-heterocyclic compounds, which can be employed as MRI contrast agents for hypoxia sensing and other molecular imaging applications.SABRE-SHEATH is a rapid, simple, cost-effective …
Temperature Dependence Of The Electronic Absorption Spectrum Of No2,
2023
Missouri University of Science and Technology
Temperature Dependence Of The Electronic Absorption Spectrum Of No2, Steve Ndengué, Ernesto Quintas Sánchez, Richard Dawes, Christopher C. Blackstone, David L. Osborn
Chemistry Faculty Research & Creative Works
The nitrogen dioxide (NO2) radical is composed of the two most abundant elements in the atmosphere, where it can be formed in a variety of ways including combustion, detonation of energetic materials, and lightning. Relevant also to smog and ozone cycles, together these processes span a wide range of temperatures. Remarkably, high-resolution NO2 electronic absorption spectra have only been reported in a narrow range below about 300 K. Previously, we reported [ J. Phys. Chem. A 2021, 125, 5519−5533 ] the construction of quasi-diabatic potential energy surfaces (PESs) for the lowest four electronic states (X̃, Ã, B̃, …
Impact Of Sample Conditions On Dna Phosphodiester Backbone Bi/Bii Conformational Equilibrium Dynamics,
2023
Missouri State University
Impact Of Sample Conditions On Dna Phosphodiester Backbone Bi/Bii Conformational Equilibrium Dynamics, Autumn C. Pilarski
Graduate Theses/Dissertations
DNA damage, such as single base lesions and mismatches, is highly prevalent within cells. If these DNA damage events are not repaired, they could lead to mutations and thus disease and cancer. Intricate repair mechanisms are in place to fix these damage events, one such being Base Excision Repair (BER) and associated enzyme: Thymine DNA Glycosylase (TDG). The first step of this repair process, recognition of the lesion by TDG, is not well understood. The following thesis presents results to better understand the fundamental biophysical question of how a DNA lesion within a mismatch context is recognized in a million …
Triplet Sensitization Enables Bidirectional Isomerization Of Diazocine With 130 Nm Redshift In Excitation Wavelengths,
2023
Tampere University, Finland
Triplet Sensitization Enables Bidirectional Isomerization Of Diazocine With 130 Nm Redshift In Excitation Wavelengths, Jussi Isokuortti, Thomas Griebenow, Jan-Simon Von Glasenapp, Tim Raeker, Timo Laaksonen, Rainer Herges, Nikita A. Durandin
Articles
Diazocines are bridged azobenzenes with phenyl rings connected by a CH2–CH2 group. Despite this rather small structural difference, diazocine exhibits improved properties over azobenzene as a photoswitch and most importantly, its Z configuration is more stable than the E isomer. Herein, we reveal yet another unique feature of this emerging class of photoswitches. In striking contrast to azobenzenes and other photochromes, diazocine can be selectively switched in E / Z direction and most intriguingly from its thermodynamically stable Z to metastable E isomer upon successive excitation of two different triplet sensitizers present in solution at the same time. This approach …
Infrared Spectra Of Small Radicals For Exoplanetary Spectroscopy: Oh, Nh, Cn, And Ch: The State Of Current Knowledge,
2023
Old Dominion University
Infrared Spectra Of Small Radicals For Exoplanetary Spectroscopy: Oh, Nh, Cn, And Ch: The State Of Current Knowledge, Svatopluk Civiš, Adam Pastorek, Martin Ferus, Sergei N. Yurchenko, Noor-Ines Boudjema
Chemistry & Biochemistry Faculty Publications
In this study, we present a current state-of-the-art review of middle-to-near IR emission spectra of four simple astrophysically relevant molecular radicals—OH, NH, CN and CH. The spectra of these radicals were measured by means of time-resolved Fourier transform infrared spectroscopy in the 700–7500 cm−1 spectral range and with 0.07–0.02 cm−1 spectral resolution. The radicals were generated in a glow discharge of gaseous mixtures in a specially designed discharge cell. The spectra of short-lived radicals published here are of great importance, especially for the detailed knowledge and study of the composition of exoplanetary atmospheres in selected new planets. Today, …
Telp Theory: Elucidating The Major Observations Of Rieger Et Al. 2021 In Mitochondria,
2023
Old Dominion University
Telp Theory: Elucidating The Major Observations Of Rieger Et Al. 2021 In Mitochondria, James Weifu Lee
Chemistry & Biochemistry Faculty Publications
The transmembrane-electrostatically localized protons (TELP) theory may represent a complementary development to Mitchell's chemiosmotic theory. The combination of the two together can now excellently explain the energetics in mitochondria. Our calculated transmembrane-attractive force between an excess proton and an excess hydroxide explains how TELP may stay within a 1-nm thin layer at the liquid-membrane interface. Consequently, any pH sensor (sEcGFP) located at least 2–3 nm away from the membrane surface will not be able to see TELP. This feature as predicted from the TELP model was observed exactly in the experiment of Rieger et al., 2021. In contrast to their …
S-Type Stars: Line List For The A²Π-X²Σ⁺ Band System Of Lao,
2023
Old Dominion University
S-Type Stars: Line List For The A²Π-X²Σ⁺ Band System Of Lao, P. F. Bernath, R. Dodangodage, J. Liévin
Chemistry & Biochemistry Faculty Publications
LaO bands are found in the spectra of cool S-type stars. The bands of the A2Π–X2Σ+ transition with v' ⩽ 3 and v'' ≤ 4 are rotationally analyzed, providing spectroscopic constants for the A2Π state. Line strengths are calculated using an ab initio transition dipole moment function, and radiative lifetimes for the A2Π state have also been computed. A line list for the A2Π–X2Σ+ transition of LaO is provided and can be used to determine LaO stellar abundances.
Computational Investigation Of The Ionization Potential Of Lead Sulfide Quantum Dots,
2023
Claremont Colleges
Computational Investigation Of The Ionization Potential Of Lead Sulfide Quantum Dots, Jessica Beyer
Scripps Senior Theses
The purpose of this work was to determine the impact of quantum dot size on ionization potential and to determine how the presence of carbonyl-based ligands affect the ionization potential of lead sulfide quantum dot systems. Ionization potential (IP) is defined as the energy required to remove an electron from an atom, molecule, or material. IP helps scientists determine how reactive the material of interest is, which is crucial information when manufacturing nanomaterials. Accurate quantum chemical calculations of ionization potential are challenging due to the computational cost associated with the numerical solution of the Dyson equation. In this work, the …
Developing Novel Femtosecond Time-Resolved Mass Spectrometry Techniques For Analysis Of Energetic Materials,
2023
Virginia Commonwealth University
Developing Novel Femtosecond Time-Resolved Mass Spectrometry Techniques For Analysis Of Energetic Materials, Shane L. Mcpherson
Theses and Dissertations
Energetic materials and the unimolecular dissociation dynamics attributed to their initiation and subsequent bimolecular detonation have been a subject of interest for defense agencies such as the Department of Defense (DoD) for decades. The timescale in which these initial dynamics exist ranges from several picoseconds to dozens of femtoseconds, necessitating equally fast time-resolved experiments to capture and characterize these events. Our lab specializes in one such laser-based technique: femtosecond time-resolved mass spectrometry (FTRMS). FTRMS is an essentially nondiscriminatory pump-probe laser technique with nearly infinite modifications via pulse shaping, intensity, and wavelength modulation that can readily examine previously undefined dissociation pathways …
Molecular Elucidation Of Reaction Mechanisms In Aluminum & Lithium Metal Batteries By Solid-State Nmr Spectroscopy And Electrochemical Methods,
2023
CUNY City College
Molecular Elucidation Of Reaction Mechanisms In Aluminum & Lithium Metal Batteries By Solid-State Nmr Spectroscopy And Electrochemical Methods, Leo W. Gordon
Dissertations and Theses
As society wrestles with the ever-growing climate consequences of burning fossil fuels, the increased demand for electric vehicles and renewable power generation mandates safe, sustainable, earth-abundant, low cost, and energy dense batteries. Different use cases will necessitate different types of batteries; for example, stationary storage systems prioritize minimal expense, whereas mobile applications like electric vehicles emphasize high energy densities. Aluminum and lithium metal batteries hold great promise for next-generation energy storage due to their large specific capacities (2980 mA h g-1, and 3860 mA h g-1, respectively). In particular, aluminum metal is low cost, has high …
Electronic Structure And Molecular Geometries Of Metal Complexes With Dft And Multireference Method,
2023
University of South Dakota
Electronic Structure And Molecular Geometries Of Metal Complexes With Dft And Multireference Method, Rina Bhowmick
Dissertations and Theses
Metal complexes are ubiquitous for their diverse applications including catalysis, sensing, medicine, and environmental applications. For effective use of metal complexes, understanding their electronic structure is essential. In most cases, molecules can be represented as a single electron configuration. However, in some cases, especially transition metal and actinide complexes, multireference electronic structures are observed. This is because the valence d (and f) orbitals in metals are often nearly degenerate, leading to close-lying energy states and the subsequently more frequent presence of multiconfigurational electronic structures. The traditional approach to modeling these systems is to use density functional theory to optimize the …
Investigating The Dynamics And Fragmentation Of Nitroaromatic Radical Cations Through Femtosecond Time-Resolved Mass Spectrometry And Computational Chemistry,
2023
Virginia Commonwealth University
Investigating The Dynamics And Fragmentation Of Nitroaromatic Radical Cations Through Femtosecond Time-Resolved Mass Spectrometry And Computational Chemistry, Hugo Andres Lopez Pena
Theses and Dissertations
Chemists have sought to control molecular dissociation with lasers for decades. Effective control of unimolecular dissociation was only achieved with the development of high-intensity ultrashort pulsed lasers and coherent control techniques that operate on timescales faster than vibrational energy redistribution. In view of this, our lab has specialized in the study of polyatomic radical cations using femtosecond time-resolved mass spectrometry (FTRMS). The interest in radical cations stems from the fact that they are highly reactive species that contribute to many physical, chemical, and biological processes. For instance, radical cations participate in shock initiation of detonated energetic materials used as explosives …
Translating Chemistry, Structure, And Processing To The Solid-State Morphology And Function Of Organic Semiconductors Through Computational Modeling And Simulations,
2023
University of Kentucky
Translating Chemistry, Structure, And Processing To The Solid-State Morphology And Function Of Organic Semiconductors Through Computational Modeling And Simulations, Chamikara D. Karunasena
Theses and Dissertations--Chemistry
The immense synthetic design space and material versatility have driven the exploration and development of organic semiconductors (OSC) over several decades. While many OSC designs focus on the chemistries of the molecular or polymer building blocks, a priori, multiscale control over the solid-state morphology is required for effective application of the active layer in a given technology. However, molecular assembly during solid-state formation is a complex function interconnecting the building block chemistry and the processing environment. Insufficient knowledge as to how these aspects engage, especially at the atomistic and molecular scales, has so far limited the ability to predict …
