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 41 for “"ion-molecule"”.
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Ion-molecule reaction mass spectrometry and vacuum-ultraviolet negative photoion spectroscopy
… the fundamental properties of small polyatomic molecules in the gas phase. Selected ion flow tube mass spectrometry has been used to study the reactions of cations and anions with ethene, monofluoroethene, 1,1-difluoroethene, trifluoroethene and tetrafluoroethene. Calculated collisional reaction …
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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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A STUDY OF LOW ENERGY ELECTRON-MOLECULE AND ION-MOLECULE COLLISIONS USING RYDBERG ATOMS (IONIZATION, ASSOCIATION, ATTACHMENT, OXYGEN, WATER)
Low energy collisions between Rydberg atoms and neutral molecules have been investigated over a wide range of principal quantum numbers n, and for several different neutral targets. The results have been used to validate the free-electron, independent particle model of Rydberg atom collisions. …
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Density Functional Theory Calculations Complement Mass Spectrometry Experiments in the Investigation of Biomass Fast Pyrolysis and Ion-Molecule Reaction Mechanisms
… oxygen, is a promising method for biomass conversion necessary for a renewable energy economy. Although kinetic models of cellulose pyrolysis have existed since the 1970s, current models and hypothesized reaction networks fail to explain the product distribution even for a simple model compound, …
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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 detection of hydrazine and related materials by ion mobility spectrometry.
A technique known as ion mobility spectrometry (IMS), which has been under development for about thirty years, has been shown to be capable of detecting hydrazines at low concentrations but with interference from ammonia. Ammonia is usually present in hydrazine environments, as a breakdown product …
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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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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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Part One: The Quantitative Prediction and Analysis of Enthalpies for The Interaction of Gas Phase Ion-Ion, Gas Phase Ion-Molecule, and Molecule-Molecule Lewis Acid-Base Systems. Part Two: The Study of Intervalence Transfer in Mixed Valence Systems Using Time Domain Reflectometry
In Part One, the equation -(DELTA)H = e(,A)e(,B) + c(,A)c(,B) + t(,A)t(,B) where the subscripts A and B refer to acid and base correlates the enthalpy of Lewis acid-base adduct formation for molecule-molecule, gas phase ion-molecule, and gas phase ion-ion interactions. The parameters obtained are …
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SOLVATION OF ORGANIC CATIONS IN THE GAS PHASE AND WITHIN MOLECULAR CLUSTERS
The role of the solvent in ionic and ion-molecule interactions is of fundamental importance in kinetics and thermodynamics of solution chemistry. However, the study of the ionic interactions in the presence of a large number of solvent molecules is very challenging. Therefore, the gas-phase is the …
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Elucidating the Hydration of Biomolecules: An Experimental and Computational Approach
… for differences between gas-phase and solution-phase systems, a better understanding of how competitive noncovalent interactions affect the hydration and structure of flexible biomolecules can be gleaned. By systematically probing inherent gas-phase properties, such as, solvation shell size …
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Thermoionization and dissociation of fullerenes and endohedral fullerenes
<p>Electron emission and unimolecular dissociation of energetically excited fullerenes and endohedral fullerenes are studied with mass spectrometry. Three experimental approaches have been developed for these studies. These are UV laser excitation time-of-flight mass spectrometry (TOF-MS), laser …
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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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Atmospheric Aerosol Particle Formation : Aircraft-Based Mass Spectrometric Measurements of Gaseous and Ionic Aerosol Precursors
The condensational growth of aerosol particles and the formation of fresh, nanometer-sized particles depend primarily upon the presence of H2SO4. Atmospheric ions produced by cosmic rays can initialize the formation of clusterions, which subsequently may grow by mutual coagulation and condensation …
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