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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 43 for “"Ab Initio Molecular Dynamics"”.
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Ab initio molecular dynamics simulations of lanthanide coordination structures in water and in faujasite
Atomic and molecular resolution can provide unique insights into the ambiguous mechanisms by which lanthanum increases the hydrothermal stability of faujasite in cracking catalysts, as well as in cation exchange in faujasite. The structures of the lanthanide aqua ions were resolved with density …
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Hydrolysis and aqueous corrosion of silicate and aluminosilicate glasses via ab initio molecular dynamics simulation
… aluminosilicate bulk glasses are simulated using ab initio molecular dynamics (AIMD). The atomic origin of the hydrolysis reaction is analyzed, and its effects on the structural, electronic, mechanical, and optical properties of the studied glasses are explored. A complete picture of interatomic …
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Transition path sampling in organometallic catalysis: Overcoming the rare event problem in ab initio molecular dynamics
… free energies using the harmonic approximation. Ab initio molecular dynamics (AIMD) is an obvious strategy to address these issues. Within these simulations, the full range of thermally accessible structures is explored and anharmonicity is expressed intrinsically. As AIMD simulations are …
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Exploring kinetics and thermodynamics in fast-ion conductors and hydrogen-storage materials using ab-initio molecular dynamics
… (CsHSO4), and sodium alanate (NaAlH4)-using ab-initio molecular dynamics simulations. The time-averaged and instantaneous silver substructure in the fast-ion conductor AgI is analyzed, resulting in a set of ordering rules that govern the distribution of the mobile silvers in the first …
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Ab-initio molecular dynamics studies of laser- and collision-induced processes in multielectron diatomics, organic molecules and fullerenes
This work presents applications of an ab-initio molecular dynamics method, the so-called nonadiabatic quantum molecular dynamics (NA-QMD), for various molecular systems with many electronic and nuclear degrees of freedom. Thereby, the nuclei will be treated classically and the electrons with …
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Improving Understanding of Lithium-Oxygen Batteries Using Atomistic Simulations
… project, I explored one simulation methodology, ab initio molecular dynamics, commonly used to model battery systems. I examined the coordination environment of lithium ions in different solvents and compared the computational results to experimental data. The result was that the computationally …
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Exploration of the Application of Machine Learning to the Improvement of Interatomic Potentials
… suffer from limitations which restrict the ability of the simulations to correctly characterize certain material behavior and physical phenomena. Small scale ab initio molecular dynamics (AIMD) modeling is highly accurate but is computationally expensive. Classical molecular dynamics (CMD) …
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Accelerated atomistic prediction of structure, dynamics and material properties in molten salts
… remain many uncertainties in the chemistry, dynamics and physicochemical properties of many salts, especially over the course of reactor operation, where impurities are introduced, and compositional and thermodynamic changes occur. Density functional theory (DFT) and ab initio molecular …
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Metalloid aluminum clusters with fluorine
… combustion. There is recent interest in using molecular-scale metalloid clusters as a way to achieve very rapid rates of metal combustion. These clusters contain a mixture of low-valence metals as well as organic ligands. Here we investigate a prototypical aluminum metalloid cluster to …
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Temperature dependent structural, electronic and optical properties of the Si(100) surface from first principles
… simulations for the Si bulk and Si(100) surface; ab-initio molecular dynamics (AIMD) using the Car-Parrinello Molecular Dynamics formalism (CPMD) and Born-Oppenheimer Molecular Dynamics (BOMD), related vibrational states (surface phonons) by calculating the vibrational density of states (VDOS) …
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Numerical Constitutive Modelling for Continuum Mechanics Simulation
… results which are predictive, with applicability to a wide class of materials, and with a systematic way to apply the techniques to any particular material of interest. We apply these techniques to silicon. The first investigation aims at developing an equation of state model for …
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Dynamical effects in crystalline solid state systems: theory of temperature dependent optical response of bulk gaAs and vibrational modification of C(111) 2 x 1 Surface in Comparison to Experiment
… This research, fundamental by nature, brings about a deeper understanding of the dynamical processes in a range of materials. This establishes technologically important correlation with experimentally measured macroscopic properties and materials characterization. This method—the first of its …
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Multiscale computational modeling of nanofluidic transport
… to better understand the mechanisms of intrinsic molecular interaction in nanofluidic applications. We performed ab initio molecular dynamics to study the nanoscale solvation behavior of selected ions on finite graphene models. The degree of charge transfer between ion and water, and the effect of …
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Ab initio calculations of NMR chemical shifts for structure determination in biology
… shift in the solid are studied by combinig ab initio molecular dynamics simulations and NMR chemical shift calculations. Other factors affecting the chemical shift are investigated by constructing ideal models from which we can extract information about the nature of the hydrogen bonds in …
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Structure and properties of the interdiffused phase between lithiated silicon and copper current collector
… from the Cu current collector and inevitably results in capacity fade. Using first principle calculations based on density functional theory and ab-initio molecular dynamics simulations, this thesis focuses on the structure of the Cu/Si interface and aims to provide a complete picture of …
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Molecular Simulation of Zeolites by Machine-Learned Potentials
… ion exchange. Zeolites exhibit significant variability in the morphology and dimensions of their pores and channels, which directly influences their suitability for specific applications depending on the molecules intended for incorporation. By systematically screening a comprehensive array of …
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Spectra at speed: neural force fields for IR spectroscopy in ionic liquids
… near room temperature. Their structural tunability grants unique properties, making them valuable in catalysis, separations, and electrochemical energy storage. Understanding their microscopic structure and dynamics is key to optimizing such applications. Infrared (IR) spectroscopy provides …
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Ionic conductivity transitions in antiperovskite ionic conductors
… diffraction, nuclear magnetic resonance and ab initio molecular dynamics simulation, we show that the 100x increase in ionic conductivity in stoichiometric AP Na₃OCl is related with an octahedral to cubic phase transition with increasing octahedral tilt disorder. We then present two novel …
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Perovskite interfaces with protective zinc compounds – DFT computation and related experiments
… structural strategies to enhance their stability, but the interfacial interactions between soft perovskite core-shell materials remain poorly understood. This thesis systematically studies the interfaces between perovskite nanocrystals and protective shells made of zinc compounds such as …
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Modeling real world phenomena using molecular dynamics and continuum simulations
… surface. It was observed that the sticking probability of ice-like argon aggregate is higher than that of the amorphous SiO 2 aggregate when incident on the HOPG surface. The sticking probability of SiO 2 is significantly higher than that of the ice-like argon aggregate at 1.5 km/s on the quartz …
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