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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 21 for “"molecular clusters"”.
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Electron Attachment To Small Molecular Clusters
… gas-phase and surrounded by water (forming small clusters). We provide a comparison of pyridine and pyridine-H<sub>2</sub>O calculations for various standard scattering models (Static Exchange, Static Exchange plus Polarization and Close-Coupling). For pyridine-(H<sub>2</sub>O)<sub>n'</sub> n = 2, …
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SOLVATION OF ORGANIC CATIONS IN THE GAS PHASE AND WITHIN MOLECULAR CLUSTERS
… appropriate medium to study such reactions on a molecular level where the ion-solvent interaction can be examined by studying ions surrounded with a cluster of solvent molecules in the complete absence of the any interference caused by the bulk of the solvent. In nature, organic ions can form …
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Development of an Apparatus for the Study of Electron Impact Fragmentation of Molecular Clusters
… in this thesis was to generate a beam of molecular clusters and to look at fragmentation processes induced by low-energy electron impact. These processes are studies by time-of-flight detection of ionised and neutral metastable fragments. A beam of molecular clusters is generated using a …
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Gas Phase Studies of Molecular Clusters Containing Metal Cations, and the Ion Mobility of Styrene Oligomers
… of a variety of metal cations by benzene clusters have been studied using laser vaporization, cluster beam and time-of-flight mass spectrometry techniques. In this work strong magic numbers were observed for clusters containing 10, 13 and 14 benzene molecules depending on the nature of the …
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BINDING ENERGIES AND SOLVATION OF ORGANIC MOLECULAR IONS, REACTIONS OF TRANSITION METAL IONS WITH, AND PLASMA DISCHARGE IONIZATION OF MOLECULAR CLUSTERS
… and growth mechanisms of carbon-containing molecular ions with relevance to astrochemistry. Ion mobility mass spectrometry and DFT computations were used to investigate how a second nitrogen in the pyrimidine ring will affect the formation of a covalent bond between the benzene radical …
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From adsorption to condensation: The Zeta adsorption isotherm approach
… adsorb on a solid surface as a collection of molecular clusters. The theory is extended to the steady, thermal disequilibrium states where a vapour at a temperature T^V is exposed to a solid surface at a lower temperature, T^S, and the adsorption of the vapour on a homogenous solid surface is …
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An outcome-based statistical framework to select and optimize molecular clustering methods for infectious diseases
… pathogens allows for the construction of molecular clusters: groups of cases with genetically similar pathogen populations. These imply outbreaks, but the methods used to create them often require a threshold to qualify clusters (ie. 99% average pairwise sequence identity among cases). …
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Interactions of pure aluminium hydrolytic species Keggin polyoxocations and hydroxide with biologically relevant molecules
… hydrolysis-condensation of aluminium-ions into molecular clusters, structural conversion of aluminium Keggin-like polynuclear clusters into nanoparticles of aluminium (oxy) hydroxide, aggregation of primary nuclei of aluminium (oxy) hydroxide into larger clusters and finally the 'arrested …
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Noncovalent Interactions Involving Microsolvated Networks Of Trimethylamine N-Oxide
… calculations on explicit hydrogen bonded molecular clusters. The similarities in the Raman spectra of microsolvated TMAO using a variety of hydrogen bond donors suggest a comstructural motif in all of the hydrogen bonded complexes. In particular, the arrangement of hydrogen bonds with …
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Determination of Noncovalent Intermolecular Interaction Energy from Electron Densities
<p>Noncovalent intermolecular interactions, widely found in molecular clusters and bio-molecules, play a key role in many important processes, such as phase changes, folding of proteins and molecular recognition. However, accurate calculation of interaction energies is a very difficult task because …
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Insights into formation of semiconductor nanocrystals : from first principles calculations to kinetic models of nucleation and growth
… of formation of active growth species and small molecular clusters. We further explore the effect of ligand stabilization on cluster formation. In the second part, we explore reactions occurring on various surfaces of CdSe at later stages of crystal growth using periodic density functional theory …
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Quantitative Theories of Nanocrystal Growth Processes
… to be digested further from nanocrystals into molecular clusters that eliminate all crystalline material in favor of surfactant-crystal coordination. The outstanding question is, why does the spontaneous digestive ripening process appear to make large nanocrystals shrink to small nanocrystals, …
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Ring-polymer approaches to instanton theory
Inspired by the success of the ring-polymer molecular dynamics (RPMD) method, we derive a transition-state-theory version (RPTST) with a dividing surface which is, in general, conical in ring-polymer space. It is explained why this conical form is a good approximation to the optimal dividing …
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Uncovering Structure-Property Relations in Biomimetic Lipid Membranes with Molecular Additives
… cell membranes, exemplifies a highly adaptable molecular assembly with characteristics that have been fine-tuned through evolution to meet the diverse functional needs of cells. These bilayers must strike a delicate balance: they need to be sufficiently rigid to act as protective barriers, yet …
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Unsupervised Multi-Scale Analysis for the Identification of Placental Subtypes of Human Preeclampsia and Fetal Growth Restriction
… large microarray datasets revealed 3-5 molecular clusters, depending on the study. However, three subtypes of PE placentas were consistently identified within clusters 1-3, and, eventually, each co-clustered with a group of placentas from normotensive suspected FGR pregnancies. Within …
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Preparing Main Group Metal Clusters from Organoaluminium Reagents; New Possibilities in Alkali-Activated Polymer Crosslinking
… AlR3, led to the formation of different Al-based molecular clusters, depending on the nature of R, the reaction stoichiometry and the character of the benzoic acid derivative. The obtained compounds were characterised in the solid state by X-ray diffraction methods and two main motifs were …
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High-resolution infrared spectroscopy of large molecules and water clusters using quantum cascade lasers
… detailed information about molecules and molecular clusters. This dissertation presents several high-resolution spectroscopic studies of large molecules and water clusters which have been obtained using a quantum cascade laser (QCL) based infrared spectrometer coupled to a supersonic …
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The Ab Initio Calculation of the Chemical Shift Tensor and its Application for the Structure Determination in Ordered and Disordered Phases by Means of Solid-State Nuclear Magnetic Resonance
… of isolated molecules over hydrogen bonded molecular as well as polymeric phases to covalently bonded two-dimensional layered compounds. For the structural modeling in these environments the advantages of force field and semiempirical methods, density functional and perturbation theory …
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Drift Tube Ion Mobility Measurements for Thermochemistry, Kinetics and Polymerization of Cluster Ions
… The measured binding energies of the hydrated clusters of 9-12 kcal/mol are typical of carbon-based CH+•••X hydrogen bonds. The ion solvation with the more polar CH3CN molecules results in stronger bonds consistent with the increased ion-dipole interaction. Ab initio calculations show that the …
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Quantum-size effects in the electronic structure of novel self-organized systems with reduced dimensionality
… and as templates for self-organization of Au nanoclusters. Photon energy dependent photoemission revealed a surface resonance which was never observed before on W(110) which is the base plane of the terrace microsurfaces. The dispersion E(k) of this state measured on stepped W(331) and W(551) with …
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