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 22 for “"potential energy landscape"”.
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Development Of New Algorithms For Exploring The Potential Energy Landscape Of Chemical Reactions
… either ab initio or density functional theory potential energy surfaces.</p> <p> The final two chapters of this thesis focus on the development of a new path optimization framework, the Variational Reaction Coordinate (VRC) method. This framework seeks to improve upon the “chain of states” …
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Molecular Simulation Studies of Physical Aging and Rejuvenation in Polymer Glasses
This thesis provides the potential energy landscape description of mobility enhancement that follows deformation of polymer glasses. We show that there are two mechanisms which dictate the mobility enhancement – fold-catastrophe mechanism which reduces the barrier between the minima; and …
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Experimental Interrogation Of One-Dimensional Excitons In Cadmium Selenide And Cadmium Telluride Quantum Nanostructures
… cross sections make them quite attractive for potential use in photovoltaic and optoelectronic devices. The quantum-confined radial dimension of quantum wires increases the coulombic interaction between photo-generated excitons, and therefore increase the exciton binding energy as compared to …
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Understanding long timescale phenomena in atomic systems from accelerated molecular simulation methods
… the crossing by thermal activation of large energy barriers, which represent transition states separating two stable or metastable states of a system. Therefore, we propose two methods to simulate the escape of a system from a metastable state to a transition state, which, when repeated, …
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Kinetic metallic glass evolution model
… stimuli. The foundation of this model is a potential energy landscape; this consists of three pieces: a function for the energy of any given stable state, a density of states function across the landscape, and a model for the energetic barriers between stable states. All three of these …
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Thermodynamic signatures for hexapeptides with propensity for phase separation and amyloid formation
… of these collective behaviour properties in the potential energy landscape of monomers and dimers of IDPs. The landscapes of short hexapeptide sequences are explored here. Some of these hexapeptides are chosen to encode aromatic–aromatic and cation–aromatic interactions that are known to drive …
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Higher Order Structure in the Energy Landscapes of Model Glass Formers
… the behaviour of supercooled liquids and their energy landscapes is well established and widely accepted. Understanding this link would be a key step towards resolving many of the mysteries and controversies surrounding the glass transition. Therefore the study of glassy energy landscapes is an …
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Global Structure Search of Nickel Clusters Using Basin Hopping and Gaussian Approximation Potential
… their atomic configuration. Predicting their low-energy structures remains challenging due to the complex potential energy landscape associated with metallic bonding. Accurately predicting the configurations of Ni clusters is essential for understanding their fundamental properties and advancing …
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Atomistic characterization of stress-driven configurational instability and its activation mechanisms
… by systematically probing the atomistic potential energy landscape of each system using the state of the art configurational space sampling schemes. The problems studied are homogeneous dislocation nucleation in a perfect crystal by nanoindentation, dislocation emission and cleavage …
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Enhanced transport through confined channels by stationary and fluctuating potentials
… optical tweezers are used to modulate the potential energy landscape in those channels. We show how to extract the underlying energy potential by analysing local transition probabilities. Our method is applicable both to equilibrium systems and non-equilibrium steady states. Our method …
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Particle separation via the hybrid application of optical and acoustic forces
… radiation force balancing is observed in a 3D potential energy landscape, using similar principles as seen in particle trapping with counter-propagating beams. Tuning of the radiation force balance in this system allows particles to, instead of being pinned to the surface by the radiation force …
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Direct energy landscape sampling of the homogeneous nucleation and crystal growth of a model liquid
… processes involving the crossing of free-energy barriers. Attempts to capture the entire crystallization process over long timescales with molecular dynamic simulations have met major obstacles because of the temporal constraints of molecular dynamics. Herein, we circumvent this temporal …
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Equilibration of deep neural networks and carrier chirality in Rashba systems
… This allows us to interpret the loss function landscape of deep neural networks as the counterpart of the potential energy landscape in molecular systems and the optimisation of the network as its equilibration dynamics. Using landscape exploration tools developed in theoretical chemistry, we …
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Simulation studies of Brownian motors
… particles using a time dependent, asymmetric potential energy landscape, and the transport speed of the ratchet can be increased if information about the particle distribution is incorporated as feedback in the time dependency of the landscape. Using a Langevin Dynamics simulation, we compare …
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Imaging Single-Electron Charging in Nanostructures by Low-Temperature Scanning Force Microscopy
… and exemplify how to extract their charging energy from the AFM measurements. We frequently observe interaction between neighboring quantum dots and characterize their interdot coupling. The evolution of the quantum dots in CNTs with gate voltage reflects the underlying potential energy …
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Vibrational and mechanical properties of disordered solids
… directly from their microscopic structure and potential energy landscape at zero temperature. In this thesis different types of disordered systems were studied using this framework. By comparing the shear modulus and vibrational properties of nearest neighbour spring networks based on depleted …
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Energy Landscaping - On the Relationship between Functionality and Sequence Mutations for Multifunctional Biomolecules
… of as being guided by a folding funnel on the energy landscape, which is based around the native structure. However, more recently, various biomolecules have been associated with multifunnel energy landscapes, where each funnel exhibits a distinct structural ensemble and function. This work …
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Dynamics and Equilibria of N Point Charges on a 2D Ellipse or a 3D Ellipsoid
… We characterize these based on their total potential energies. Some of the equilibria found turn out to represent local minima in the potential energy landscape, while others represent the global minimum. We devise a method based on comparing the moment-of-inertia tensors of the final …
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Nanoscale modeling of materials: post deposition morphological evolution of fcc metal surfaces
… using a saddle-point search method in the potential energy landscape. The speed of the simulations is thus enhanced along with a substantial gain in reliability. Using this method the diffusion and coalescence of two-dimensional Cu and Ag adatom-island on Cu(111) and Ag(111) is studied. …
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Design of Single-Chain Polymer Nanoparticles to Mimic Globular Proteins
… including compactness, monomer hydration, and potential to stabilize membrane protein are largely insensitive to sequence, but strongly depend on composition. At the core of their behavior lies a phenomenon known as hydration frustration, where polar groups become dehydrated and hydrophobic …
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