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 25 for “"cluster ions"”.
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Competition Between Different Non-Covalent Interactions in Cluster Ions
Non-covalent interactions are important in ionic systems, where ion-molecule interactions must compete with molecule-molecule interactions. This competition between different non-covalent interactions ultimately governs the behavior of many processes. In this Thesis, competing noncovalent …
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Drift Tube Ion Mobility Measurements for Thermochemistry, Kinetics and Polymerization of Cluster Ions
… 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 discussed. The ion hydration study is focused on the C3H3+ cation1 …
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Infrared spectroscopy of cluster ions: High energy conformer trapping and multiple photon absorption
… predissociation (IRPD) spectra of several cluster ions are presented, resulting in the emergence of two major themes. Trapped, high energy conformers are observed in argon tagged clusters. In non-argon tagged hydrated alkali metal ion clusters, multiple photon absorption processes can …
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Study of the Interplay Among Non -Covalent Interactions in Structural Determination of Gas Phase Cluster Ions
The cesium and lithium ions were also investigated with benzene and water. Unimolecular dissociation rates were used to determine the most labile species and therefore a possible structural change. In the vibrational spectra of Li+(Benzene)n(Water)1--4 clusters, pi-H bonding bands dominated, while …
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Charge and temperature effects on biomolecule hydration: an experimental and computational investigation
… and temperature on the structure of hydrated cluster ions. This is investigated using a combination of infrared photodissociation (IRPD) spectra and geometry and frequency calculations. The particular cluster ions examined here include hydrated rubidium cluster ions and hydrated sodium- and …
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An Experimental and Computational Study of Noncovalent Interactions in Gas Phase Ion Solvation
… combination of techniques for the study of cluster ions and thereby the intermolecular interactions which govern their structure.
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MANIPULATION OF ELECTROSPRAY GENERATED DROPLETS USING VARIOUS VAPORS
… to form alkali metal adducted reagent vapor cluster ions that are ionized via the ion evaporation model, which reduces the amount of alkali metal in the electrospray droplet available to adduct to proteins that are ionized via the charge residue model. Polar vapors can be used to stabilize …
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Infrared spectroscopy and Monte Carlo simulations of gas phase, solvated alkali ions
The solvation of the alkali ions Na$\sp{+}$ and Cs$\sp{+}$ by methanol has been investigated by gas-phase vibrational spectroscopy and Monte Carlo simulations of small ion clusters: Na(CH$\sb3$OH) $\sbsp{\rm N}{+}$, N = 6 to 15 and Cs(CH$\sb3$OH) $\sbsp{\rm N}{+}$, N = 4 to 25. The solvated ions, …
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Effects of implementation of decaborane ions in silicon
The next generations of Si microelectronic devices will require ultra shallow p-type junctions formed by implantation of B ions with energies below 1 keV, at which available beam currents are severely limited by space charge effects. To solve this problem, decaborane (B_{10}H_{14}) cluster ion …
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Low energy implantation of boron with decaborane ions
… approach to forming ultra shallow p-type junctions (tens of nm.) needed for future generations of Si MOS devices. In the new approach, B dopant atoms are implanted by cluster ions obtained by ionization of decaborane (B_{10}H_{14})vapor. Each B atom carries only ~9% of the cluster kinetic …
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The investigation of solvent shell structure and reactivity in solvated metal ion clusters
The structure and reactivity of gas phase ionic clusters were studied using molecular beam mass-spectrometry, vibrational predissociation spectroscopy and Monte Carlo simulation. Cluster ions of the form M$\sp+$(S)$\sb{\rm N}$, M = Cs, Na and S = CH$\sb3$OH, NH$\sb3$, CH$\sb3$NH$\sb2$, …
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Characterization of Oligosaccharides and Nanoparticles by MALDI-TOF Mass Spectrometry
The possibilities of differentiating linkage positions and anomeric configurations of small oligosaccharides by negative ion mode MALDI using anion attachment followed by PSD are investigated. By careful initial adjustment of the focusing mirror ratios allowing acquisition of the peaks of interest …
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Photophysics of hexanuclear [Re₆Q₈]²⁺ cluster compounds
… that are currently used for these applications are typically emissive compounds whose emission intensity is quenched by oxygen. This measurement of oxygen concentration at a surface can be used to calculate the pressure, and thus the flow. Although most PSP probes are used at or around …
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Mechanistic Insights into Analyte Charge Enhancement using Mass Spectrometry and Molecular Dynamics Simulations
… a combination of molecular dynamics (MD) simulations and experiments to gain insights into the hidden complexities of ESI-MS. The structure and reactivity of electrosprayed protein ions is governed by their net charge. In Chapter 2, we sought to uncover the mechanistic basis of La3+-induced …
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Characterization Of Charge Accommodation In Biologically Important Hydrogen-Bonded Clusters
… Here, we look at bulk phase and gas phase clusters to compare the local hydrogen-bonded network. To better understand the role noncovalent interactions have on biologically relevant building blocks in a natural environment, we compare the microhydration of gas phase cluster ions to …
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UV Induced Processes in Biomolecules, Hydrated Clusters and Stark Deflected Beams
… elucidated. This represents a barrier to innovations in radiotherapy and also limits our understanding of the molecular origins of life. Experiments on gas-phase biological building blocks can reveal detailed information via comparisons with high-level calculations, while parallel studies of …
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The application of low dose SIMS to surface studies on compound semiconductors
… the sensitivity of SIMS to molecular cluster ions from contamination on the surface. This sensitivity proved a useful tool for determining the likely sources of contamination. The sensitivity of the (111)PbTe surface to surface damage produced by ion bombardment, prevented a conclusive …
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Rare-gas clusters in intense VUV laser fields
… approach to the interaction of atomic clusters with intense laser fields in the vacuum ultra-violet (VUV) has been developed. Much emphasis is put on localized electrons, those quasi-free electrons which localize about the ions and screen them. These electrons set a time scale, which is …
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Ionic conductivity transitions in antiperovskite ionic conductors
… also provide an ideal system to study the relationship between disorder and ionic conductivity, as in AP system the degree of lattice disorder can be easily tuned through atom substitution and the incorporation of cluster ions. Moreover, some AP compounds exhibit non-linearity in the Arrhenius …
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