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Imaging The Dynamics Of Ch2bri Photodissociation In The Near Ultraviolet Region, Changen Pan 2018 College of William and Mary

Imaging The Dynamics Of Ch2bri Photodissociation In The Near Ultraviolet Region, Changen Pan

Undergraduate Honors Theses

The photodissociation dynamics of jet-cooled CH2BrI are investigated in the near-ultraviolet (UV) region from 280 – 310 nm using velocity map imaging. We report the translational and internal energy distributions of the CH2Br radical and ground state I (2P3/2) or spin-orbit excited I (2P1/2) fragments determined by velocity map imaging of the ionized iodine fragments following 2+1 resonance-enhanced multiphoton ionization of the nascent neutral iodine products. The velocity distributions indicate that most of the available energy is partitioned into the internal energy of the CH2Br radical with only ...


Photo-Controlled Release Of Zinc Ions In Aqueous Solution With Simultaneous Fluorescence Detection, Tyler Larson 2018 College of William and Mary

Photo-Controlled Release Of Zinc Ions In Aqueous Solution With Simultaneous Fluorescence Detection, Tyler Larson

Undergraduate Honors Theses

We created a system consisting of a highly fluorescent conjugated polymer nanoparticle paired with a photo-release dye. Upon irradiation at the maximum absorbance of the nanoparticle, it non-radiatively transfers its energy to the dye through the process of FRET (Fluorescence Resonance Energy Transfer), exciting the dye, which then releases a biologically relevant ion, zinc. This system enhances the photo-release process, making it kinetically faster and more efficient. The photo-event is accompanied by a change in fluorescence of the dye, allowing for simultaneous detection of photo-release. This thesis outlines nanoparticle synthesis using the reprecipitation method, synthesis of the zinc releasing dye ...


Hyperpolarization Of Silicon Nanoparticles With Tempo Radicals, Jingzhe Hu, Nicholas Whiting, Pratip Bhattacharya 2018 University of Texas MD Anderson Cancer Center

Hyperpolarization Of Silicon Nanoparticles With Tempo Radicals, Jingzhe Hu, Nicholas Whiting, Pratip Bhattacharya

Nicholas Whiting

Silicon-based particles can be hyperpolarized via dynamic nuclear polarization to enhance 29Si magnetic resonance signals. Application of this technique to nanoscale silicon particles has been limited because of the low signal enhancements achieved; it is hypothesized that this is due to the low number of endogenous electronic defects inherent to the particles. We introduce a method of incorporating exogenous radicals into silicon nanoparticle suspensions in order to improve the hyperpolarization of 29Si nuclear spins to levels sufficient for in vivo MR imaging. Calibration of radical concentrations and polarization times are reported for a variety of silicon particle sizes (30−200 ...


Multiresonant Anisotropic Nanostructures For Plasmon-Mediated Spectroscopies, Gregory Q. Wallace 2018 The University of Western Ontario

Multiresonant Anisotropic Nanostructures For Plasmon-Mediated Spectroscopies, Gregory Q. Wallace

Electronic Thesis and Dissertation Repository

To detect and analyze molecular species of interest, analytical sciences and technologies exploit the variation in the chemical properties associated with the analytes. Techniques involving vibrational spectroscopy rely on the unique response observed when a molecule interacts with light. Although these methods can provide the specificity needed for detection, they are traditionally hindered by the need for large quantities of material, and long acquisition times. To minimize these issues, advancements in plasmon-enhanced techniques, such as surface-enhanced Raman spectroscopy (SERS) and surface-enhanced infrared absorption (SEIRA) are being made. Such techniques make use of the strong interaction between an optical field and ...


Electrochemical And Corrosion Examination Of Copper Under Deep Geologic Conditions For The Application Of Nuclear Waste Containers, Taylor L. Martino 2018 The University of Western Ontario

Electrochemical And Corrosion Examination Of Copper Under Deep Geologic Conditions For The Application Of Nuclear Waste Containers, Taylor L. Martino

Electronic Thesis and Dissertation Repository

Copper is the selected material for the fabrication of nuclear fuel waste containers in Sweden, Finland and Canada due to its corrosion resistance in the anoxic aqueous environments, anticipated in deep geological repositories. A potential oxidant for copper is bisulphide produced either by the dissolution of minerals or by sulphate-reducing bacteria. The primary goals of this thesis were to determine the mechanism of corrosion of copper in bisulphide environments and to investigate the chemistry of the bentonite porewater that will ultimately be in contact with the copper container.

The mechanism of sulphide film growth and the details of copper corrosion ...


Liquid-Like Thermal Conduction In Intercalated Layered Crystalline Solids, B. Li, H. Wang, Y. Kawakita, Q. Zhang, M. Feygenson, H. L. Yu, D. Wu, K. Ohara, T. Kikuchi, K. Shibata, T. Yamada, X. K. Ning, Y. Chen, J. Q. He, David Vaknin, R. Q. Wu, K. Nakajima, M. G. Kanatzidis 2018 Japan Atomic Energy Agency

Liquid-Like Thermal Conduction In Intercalated Layered Crystalline Solids, B. Li, H. Wang, Y. Kawakita, Q. Zhang, M. Feygenson, H. L. Yu, D. Wu, K. Ohara, T. Kikuchi, K. Shibata, T. Yamada, X. K. Ning, Y. Chen, J. Q. He, David Vaknin, R. Q. Wu, K. Nakajima, M. G. Kanatzidis

Ames Laboratory Accepted Manuscripts

As a generic property, all substances transfer heat through microscopic collisions of constituent particles1. A solid conducts heat through both transverse and longitudinal acoustic phonons, but a liquid employs only longitudinal vibrations2,3. As a result, a solid is usually thermally more conductive than a liquid. In canonical viewpoints, such a difference also serves as the dynamic signature distinguishing a solid from a liquid. Here, we report liquid-like thermal conduction observed in the crystalline AgCrSe2. The transverse acoustic phonons are completely suppressed by the ultrafast dynamic disorder while the longitudinal acoustic phonons are strongly scattered but survive, and are thus ...


Development Of A Semigraphitic Sulfur-Doped Ordered Mesoporous Carbon Material For Electroanalytical Applications, Jaqueline R. Maluta, Sergio A.S. Machado, Umesh Chaudhary, J. Sebastian Manzano, Lauro T. Kubota, Igor I. Slowing 2018 University of São Paulo

Development Of A Semigraphitic Sulfur-Doped Ordered Mesoporous Carbon Material For Electroanalytical Applications, Jaqueline R. Maluta, Sergio A.S. Machado, Umesh Chaudhary, J. Sebastian Manzano, Lauro T. Kubota, Igor I. Slowing

Ames Laboratory Accepted Manuscripts

The modification of traditional electrodes with mesoporous carbons is a promising strategy to produce high performance electrodes for electrochemical sensing. The high surface area of mesoporous carbons provides a large number of electroactive sites for binding analytes. Controlling the pore size and structure of mesoporous carbons and modifying their electronic properties via doping offers additional benefits like maximizing transport and tuning the electrochemical processes associated with analyte detection. This work reports a facile method to produce sulfur-doped ordered mesoporous carbon materials (S-OMC) with uniform pore structure, large pore volume, high surface area and semigraphitic structure. The synthesis used thiophenol as ...


Beyond Hydrophobicity: Aqueous Interfaces, Interactions And Reactions, Russell James Perkins 2018 University of Colorado at Boulder

Beyond Hydrophobicity: Aqueous Interfaces, Interactions And Reactions, Russell James Perkins

Chemistry & Biochemistry Graduate Theses & Dissertations (1986-2018)

Many important chemical reactions from all branches of chemistry occur with water as a solvent. Furthermore, in environmental chemistry, biochemistry, and synthetic chemistry, key reactions occur in heterogeneous aqueous systems, where interfacial effects are particularly important. Despite the importance of aqueous environments and the tremendous amount of work done to study them, there are aspects that require further explanation and remain controversial. I have performed experimental studies to help elucidate the fundamental characteristics of aqueous systems, while examining specific phenomena across several fields.

The genetic disorder phenylketonuria (PKU) can result in increased levels of the aromatic amino acid phenylalanine in ...


Origins Of The Quantum Efficiency Duality In The Primary Photochemical Event Of Bacteriorhodopsin, Robert R. Birge, Leonore A. Findsen, Albert F. Lawrence, Mark Masthay, Chian-Fan Zhang 2018 Syracuse University

Origins Of The Quantum Efficiency Duality In The Primary Photochemical Event Of Bacteriorhodopsin, Robert R. Birge, Leonore A. Findsen, Albert F. Lawrence, Mark Masthay, Chian-Fan Zhang

Mark Masthay

Experimental and theoretical evidence is presented which suggests that two distinct forms of light-adapted bacteriorhodopsin may exist. We propose that these two forms have characteristic photocycles with significantly different primary quantum yields. INDO-PSDCI molecular orbital procedures and semiempirical molecular dynamics simulations predict that one ground state geometry of bR undergoes photochemistry with a primary quantum yield, Φ1, of ~ 0.27, and that a second ground state geometry, with a slightly displaced counterion, yields Φ1 ~ 0.74. This theoretical model is supported by the observation that literature measurements of Φ1 tend to fall into one of two categories- those that observe ...


The Acs Exams Institute Undergraduate Chemistry Anchoring Concepts Content Map Iv: Physical Chemistry, Thomas A. Holme, Jessica J. Reed, Jeffrey R. Raker, Kristen L. Murphy 2018 Iowa State University

The Acs Exams Institute Undergraduate Chemistry Anchoring Concepts Content Map Iv: Physical Chemistry, Thomas A. Holme, Jessica J. Reed, Jeffrey R. Raker, Kristen L. Murphy

Chemistry Publications

The ACS Examinations Institute has been developing Anchoring Concepts Content Maps to provide an organizational template for the four-year undergraduate chemistry curriculum. In order to accomplish this goal, specific subdisciplinary versions of the map share the two top levels but distinguish themselves at the bottom two levels which contain finer-grained content details. This structure has been refined and vetted over a number of meetings and workshops. This paper presents the four levels of the content map for physical chemistry.


Uncovering The Origin Of Divergence In The Csm(Cro4)2 (M = La, Pr, Nd, Sm, Eu; Am) Family Through Examination Of The Chemical Bonding In A Molecular Cluster And By Band Structure Analysis, Shane S. Galley, Alexandra A. Arico, Tsung-Han Lee, Xiaoyu Deng, Yong-Xin Yao, Joseph M. Sperling, Vanessa Proust, Julia S. Storbeck, Vladimir Dobrosavljevic, Jennifer N. Neu, Theo Siegrist, Ryan E. Baumbach, Thomas E. Albrecht-Schmitt, Nikolas Kaltsoyannis, Nicola Lanata 2018 Florida State University

Uncovering The Origin Of Divergence In The Csm(Cro4)2 (M = La, Pr, Nd, Sm, Eu; Am) Family Through Examination Of The Chemical Bonding In A Molecular Cluster And By Band Structure Analysis, Shane S. Galley, Alexandra A. Arico, Tsung-Han Lee, Xiaoyu Deng, Yong-Xin Yao, Joseph M. Sperling, Vanessa Proust, Julia S. Storbeck, Vladimir Dobrosavljevic, Jennifer N. Neu, Theo Siegrist, Ryan E. Baumbach, Thomas E. Albrecht-Schmitt, Nikolas Kaltsoyannis, Nicola Lanata

Ames Laboratory Accepted Manuscripts

A series of f-block chromates, CsM(CrO4)(2) (M = La, Pr, Nd, Sm, Eu; Am), were prepared revealing notable differences between the Am-III derivatives and their lanthanide analogs. While all compounds form similar layered structures, the americium compound exhibits polymorphism and adopts both a structure isomorphous with the early lanthanides as well as one that possesses lower symmetry. Both polymorphs are dark red and possess band gaps that are smaller than the Ln(III) compounds. In order to probe the origin of these differences, the electronic structure of alpha-CsSm(CrO4)(2), alpha-CsEu(CrO4)(2), and alpha-CsAm(CrO4)(2) were studied ...


Innovative Monte Carlo Methods For Sampling Molecular Conformations, Aliasghar Sepehri 2018 Louisiana State University and Agricultural and Mechanical College

Innovative Monte Carlo Methods For Sampling Molecular Conformations, Aliasghar Sepehri

LSU Doctoral Dissertations

Sampling molecular conformations is an important step in evaluating physical, mechanical, hydrodynamic, and optical properties of flexible molecules especially polymers. One powerful method for this purpose is configurational-bias Monte Carlo in which one random segment of a molecule is chosen, all segments toward one random end are removed, and then regrown segment by segment to produce a new geometry to be accepted/rejected according to probability laws. The advantage of this method is the ability to generate acceptable conformations that are favorable for intra- and intermolecular energies to save computational costs. However, when there are several interdependent energetic terms, trial ...


High-Performance Flexible All-Solid-State Asymmetric Supercapacitors Based On Vertically Aligned Cuse@Co(Oh)2 Nanosheet Arrays, Jiangfeng Gong, Yazhou Tian, Ziyuan Yang, Qianjin Wang, Xihao Hong, Qing-Ping Ding 2018 Hohai University

High-Performance Flexible All-Solid-State Asymmetric Supercapacitors Based On Vertically Aligned Cuse@Co(Oh)2 Nanosheet Arrays, Jiangfeng Gong, Yazhou Tian, Ziyuan Yang, Qianjin Wang, Xihao Hong, Qing-Ping Ding

Ames Laboratory Accepted Manuscripts

The developments of electrode active materials provide the opportunities for next-generation energy storage devices. The arrangement of electrode materials on the substrate has recently emerged as a promising strategy for preparing high-performance supercapacitors. Herein, we demonstrate a novel vertically aligned CuSe@Co(OH)(2) nanosheet arrays electrode for supercapacitor application. The materials are thoroughly characterized by structural and spectroscopic techniques. Electrochemical performance of CuSe@Co(OH)(2) nanosheet arrays are investigated in detail, which exhibit a specific capacitance as much as 1180 F g(-1) at a current density of 1 A g(-1). A flexible asymmetric all-solid-state supercapacitor is ...


Investigation Of Novel Electrolytes For Use In Lithium-Ion Batteries And Direct Methanol Fuel Cells, Kartik Pilar 2018 The Graduate Center, City University of New York

Investigation Of Novel Electrolytes For Use In Lithium-Ion Batteries And Direct Methanol Fuel Cells, Kartik Pilar

All Dissertations, Theses, and Capstone Projects

Energy storage and conversion plays a critical role in the efficient use of available energy and is crucial for the utilization of renewable energy sources. To achieve maximum efficiency of renewable energy sources, improvements to energy storage materials must be developed. In this work, novel electrolytes for secondary batteries and fuel cells have been studied using nuclear magnetic resonance and high pressure x-ray scattering techniques to form a better understanding of dynamic and structural properties of these materials. Ionic liquids have been studied due to their potential as a safer alternative to organic solvent-based electrolytes in lithium-ion batteries and composite ...


Organic Photochemistry: Remote Delivery Of Reactive Oxygen Intermediates Via A Heterogeneous Approach, Niluksha Walalawela Abeykoon 2018 The Graduate Center, City University of New York

Organic Photochemistry: Remote Delivery Of Reactive Oxygen Intermediates Via A Heterogeneous Approach, Niluksha Walalawela Abeykoon

All Dissertations, Theses, and Capstone Projects

Photosensitized oxidation reactions produce a number of intermediates species, which are generated in varying amounts over time. This complexity presents major challenges in the study of oxidation processes. Mechanistic efforts to separate and deliver reactive oxygen intermediates enable their controlled use in processes such as bacterial inactivation. This thesis describes a heterogeneous reaction approach taken to control the generation and delivery of reactive oxygen intermediates. The mechanistic details of photosensitized reactions were elucidated via synthetic, materials, and physical organic techniques to optimize the delivery of reactive oxygen intermediates. This thesis contains six chapters as described below.

Chapter 1 gives a ...


Different Topological Quantum States In Ternary Zintl Compounds: Bacax (X = Si, Ge, Sn And Pb), Lin-Lin Wang, Adam Kaminski, Paul C. Canfield, Duane D. Johnson 2018 Ames Laboratory

Different Topological Quantum States In Ternary Zintl Compounds: Bacax (X = Si, Ge, Sn And Pb), Lin-Lin Wang, Adam Kaminski, Paul C. Canfield, Duane D. Johnson

Ames Laboratory Accepted Manuscripts

Topological quantum states require stringent combination of crystal symmetry and spin–orbit coupling (SOC) strength. Here, we report that the ternary Zintl compound series BaCaX (X = Si, Ge, Sn and Pb, Group IV) in the same crystal structure having eight valence electrons per formula unit can host two different topological quantum phases, controlled by atomic size and SOC strength. BaCaSi is a nodal-line semimetal (NLSM) with band inversion protected by mirror symmetry and hosts a strong topological insulator (TI) state when SOC is turned on, thus, a NLSM-TI phase. Moving to larger atomic sizes and heavier atoms, BaCaGe and BaCaSn ...


Hybrid Electrochemical Capacitors: Materials, Optimization, And Miniaturization, Richa Agrawal 2018 Department of Mechanical and Materials Engineering, Florida International University

Hybrid Electrochemical Capacitors: Materials, Optimization, And Miniaturization, Richa Agrawal

FIU Electronic Theses and Dissertations

With the ever-advancing technology, there is an incessant need for reliable electrochemical energy storage (EES) components that can provide desired energy and power. At the forefront of EES systems are electrochemical capacitors (ECs), also known as supercapacitors that typically have higher power and superior cycle longevity but lower energy densities than their battery counterparts. One of the routes to achieve higher energy density for ECs is using the hybrid EC configuration, which typically utilizes a redox electrode coupled with a counter double-layer type electrode.

In this dissertation, both scale-up (coin-cell type) as well as scale-down (on-chip miniaturized) hybrid ECs were ...


The Van Der Waals Fluid's Liquid Vapor Coexistence Locus, Carl W. David 2018 University of Connecticut

The Van Der Waals Fluid's Liquid Vapor Coexistence Locus, Carl W. David

Chemistry Education Materials

The liquid vapor coexistence locus is plotted from the analytical solution to the Maxwell construction for the van der Waals fluid.


Computational Study Of Transition Metal Complexes For Solar Energy Conversion And Molecular Interaction With Strong Laser Fields, Xuetao Shi 2018 Wayne State University

Computational Study Of Transition Metal Complexes For Solar Energy Conversion And Molecular Interaction With Strong Laser Fields, Xuetao Shi

Wayne State University Dissertations

There are two topics in this dissertation: ground state and excited state modeling of a few series of transition metal complexes that facilitate solar energy conversion, and Born-Oppenheimer Molecular Dynamics (BOMD) simulations of molecular cations interacting with intense mid-infrared laser light.

In Chapter 2 and 3, a few series of transition metal complexes that facilitate solar energy conversion are studied computationally. Metal-to-ligand charge-transfer (MLCT) excited states of several (ruthenium) (monodentate aromatic ligand, MDA) chromophore complexes are modeled by using time-dependent density function theory (TD-DFT). The calculated MLCT states correlate closely with the heretofore unknown emission properties that were observed experimentally ...


Quantitative Three-Dimensional Basal Ice Roughness From Scanning Electron Microscopy (Sem), Katie Gray, Shreeti Patel 2018 University of Puget Sound

Quantitative Three-Dimensional Basal Ice Roughness From Scanning Electron Microscopy (Sem), Katie Gray, Shreeti Patel

Summer Research

A method for analyzing the three-dimensional surface roughness on the basal facets of polar ice crystals is presented. A functional form of backscattered electron intensity as a function of ice facet orientation is adapted for the use of the basal facet. Using the Gauss-Newton inversion within a Bayesian framework a three dimensional representation of rough surfaces are retrieved at roughly micrometer resolution. Following the development of new statistical measures allow for higher statistical confidence and the connection to a scaling growth mechanism for crystal development. In a collection of results from temperatures ranging from -29 degrees celsius to -35 degrees ...


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