Global ETD Search
Search theses and dissertations gathered from participating repositories worldwide. Every result links back to the library that holds it. No account is needed.
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Showing 1 to 20 of 20 for “"Ion-molecule reactions"”.
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Measurement and kinetic analysis of complex ion-molecule reactions influenced by multiple electronic surfaces.
… and temporally resolved gas phase studies of ion-molecule reactions, particularly those featuring open-shell transition metal ions, are fundamental to understanding complex chemical reactivity paradigms that can help shed light on the behavior of bulk and extended materials. Kinetic studies …
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MASS SPECTROMETRIC INVESTIGATIONS OF STRUCTURALLY DIAGNOSTIC ION-MOLECULE REACTIONS AND OF MOLECULAR STRUCTURES OF ASPHALTENES
… tool for the molecular-level characterization of components of complex mixtures due to its ability to study ionized molecules with high sensitivity, selectivity and specificity. By combining MS/MS with liquid chromatography (LC) to enable front end separation of complex mixtures, trace …
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STRUCTURAL ELUCIDATION OF DEPROTONATED ANALYTES VIA TANDEM MASS SPECTROMETRY BASED ON ION-MOLECULE REACTIONS AND COLLISION-ACTIVATED DISSOCIATION
… a powerful analytical tool for the characterization of unknown molecules. Molecular weight information and chemical formulas of the unknowns can be derived by measuring the m/z value of the ionized analyte. In addition, structural information can be obtained via tandem mass spectrometry methods …
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Mass Spectrometric Studies on Lignin Sequencing and Fast Pyrolysis, Functional-Group Selective Ion-Molecule Reactions and Reactivity of Bi- and Triradicals
… tool for mixture analysis and structural elucidation of mixture components. Tandem mass spectrometry (MS/MS) utilizing collision-activated dissociation (CAD) has become the technique of choice for structural elucidation of unknown analytes. The coupling of MS/MS with high performance liquid …
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MASS SPECTROMETRIC STUDIES ON PETROLEUM ASPHALTENES AND ORGANOSULFUR COMPOUNDS, ON FUNCTIONAL-GROUP SELECTIVE ION-MOLECULE REACTIONS AND ON GAS-PHASE REACTIVITY OF META-BENZYNES TOWARD AMINO ACIDS
… spectrometry has found a wide variety of applications in many fields of study, such as fundamental chemistry, biological science, food and fuels, advanced materials, etc. Due to its high sensitivity, selectivity and speed, mass spectrometry provides an invaluable tool for direct mixture analysis. …
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The Temperature Dependence of Reactions of Gaseous Ions: Kinetics and Thermodynamics of Transfer and Association Reactions
… on the kinetics and thermodynamics of gaseous ion-molecule reactions were investigated by pulsed, high pressure (0.4 - 3.0 torr) mass spectrometry in the temperature range 100 - 650°K. In the context of kinetic temperature effects, the reactions investigated may be divided into three …
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GROWTH MECHANISMS OF COMPLEX ORGANICS IN THE GAS PHASE AND ON METAL NANOPARTICLES GENERATED BY A LASER VAPORIZATION PROCESS
In this dissertation, the ion mobility mass spectrometry technique is used to study the possible mechanisms of formation of polyaromatic hydrocarbons (PAHs) and polyaromatic nitrogen-containing hydrocarbons (PANHs) via the ion-molecule reactions of acetylene neutrals with different aromatic …
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Astrochemical dynamics: Fundamental studies relevant to titan's atmosphere
… results of primary fundamental photodissociation and state-specific ion-molecule dynamical studies that are relevant to understanding the formation and growth mechanisms of unsaturated hydrocarbon molecules, haze layers and aerosols in Titan's upper atmosphere. In the diacetylene dimer, it is …
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Reaction calorimetry applied to kinetic problems. The design and construction of an isothermal calorimeter with heat compensation by the Peltier effect, and the application of the calorimeter in the study of reaction kinetics in solvent/water mixtures.
… and constructed in order to investigate reaction rates in solventwater mixtures. Because a thermal method was used a constant temperature environment was essential and this was achieved by using a water bath controlled to + 0.0010C. This callorinieter has been used to study the alkaline …
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Ionisation studies of chlorinated and fluorinated compounds
Ionisation processes in gas-phase polyatomic molecules have been studied using threshold photoelectron photoion coincidence and selected ion flow tube techniques for cations and an electron attachment mass spectrometer for anions. Cation formation has been studied for fluoroform (CHF\(_3\)), …
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Growth of unsaturated, cyclic, and polycyclic aromatic hydrocarbons: Reactions under the conditions of the interstellar medium
… be carriers of interstellar infrared (IR) emission and ultraviolet (UV) absorption features. Yet, their origin in dense phases of the interstellar medium (ISM), such as molecular clouds, remains unclear. In this work, growth mechanisms based on ion-molecule reactions between cationic …
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Gas Phase Studies of Molecular Clusters Containing Metal Cations, and the Ion Mobility of Styrene Oligomers
… the mechanism of the self-initiated polymerization (or thermal polymerization) of styrene in the gas phase. In this work, we present the first direct evidence for the thermally self-initiated polymerization of styrene in the gas phase. Our approach is based on on-line analysis of the gas phase …
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Mass spectrometric characterization of remotely charged amino acids and peptides
<p>Ion–molecule reactions in a flowing afterglow are used to examine the electronic structure of 3- and 4-pyridinylnitrene-n-oxide radical anions. Reactions with nitric oxide are generally similar to those reported previously for other aromatic nitrene radical anions. In particular, phenoxide …
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Mass spectrometric characterization of peptide radical ions and implication for radical chemistry
<p>Gas-phase radical ion chemistry has attracted increasing research interest from the mass spectrometry (MS) society because it provides new capabilities in bio-analysis which often complements traditional MS methods developed from even-electron ions. Fundamental studies of biomolecule related …
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Mass Spectrometric Analysis of Thiol Proteins/Peptides Following Selenamide Derivatization And Electrolytic Reduction of Disulfide Bonds
… mass spectrometry (MS) methods such as desorption electrospray ionization-mass spectrometry (DESI-MS) provides direct ionization of analytes with little or no sample preparation. The capability for liquidsamples analysis allows DESI-MS to be coupled with many devices such as electrochemical …
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Structures and Reactivities of Ionized and Metal Cation-Containing Acetylene Clusters
In this dissertation, the ion mobility technique is used to determine the structures of small acetylene cluster ions, (C2H2)1-3+, mass-selected from the largest ever reported ionized acetylene clusters. The technique is also used to characterize the reaction of acetylene clusters with water in an …
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On the Chemistry of Molecules Containing Silicon, Phosphorus, and Sulfur in the Interstellar Medium
… its many shades. This thesis presents a collection of studies in Laboratory Astrochemistry aimed at providing new experimental data for astrochemical modeling and probing the fundamental chemistry underlying the phenomena investigated. The core of this thesis is the study of the reactivity in …
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Instrumentation and development of a mass spectrometry system for the study of gas-phase biomolecular ion reactions
<p>Gas-phase reactions of biomolecular ions are highly relevant to the understanding of structures and functions of the biomolecules. Mass spectrometry is a powerful tool in investigating gas-phase ion chemistry. Various mass spectrometers have been developed to explore ion/molecule reactions, …
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Drift Tube Ion Mobility Measurements for Thermochemistry, Kinetics and Polymerization of Cluster Ions
In this work, the Drift Tube Ion Mobility technique is used to study the hydrophobic hydration and solvation of organic ions and measure the thermochemistry and kinetics of ion-molecule reactions. Furthermore, an exploratory study of the intracluster polymerization of isoprene will be presented and …