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 14 of 14 for “"ab initio method"”.
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First-principles modeling of the amyloid-forming peptide GNNQQNY
This thesis presents an ab initio study of biological molecules using first-principles molecular dynamics. Density functional theory and Car-Parrinello molecular dynamics are used in the computational modeling of the water molecules and the amyloidforming peptide GNNQQNY derived from the yeast …
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Aspects of charge recombination and charge transport in organic solar cells and light-emitting devices
… triplet CT states in organic materials is appreciable and is material and geometry dependent. This prediction is used to guide the development of an OLED with enhanced fluorescence. The effects of nuclear disorder on optical and transport properties in organic semiconductors are examined and a …
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Probing the Nonperturbative Physics of QCD with Normalizing Flows and a moderate number of Pions
… The only known systematically improvable ab-initio method for accessing the nonperturbative physics of QCD is Lattice QCD is, and this thesis presents two advances in our understanding QCD using lattice-based methods. The first is a calculation using many-pion systems to map out the …
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Local Correlation Approaches and Coupled Cluster Linear Response Theory
Quantum mechanical methods are becoming increasingly useful and applicable tools to complement and support experiment. Nonetheless, some barriers to further applications of theoretical models still remain. A coupled cluster singles and doubles (CCSD) calculation, a reliable ab initio method, scales …
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Modelling approaches for rational solvent selection in drug development, enhancing the solubility prediction of small molecules
… industry crystallisation is the preferred method used to control crystal size and particle growth, and to purify the final product. It can also be used for the isolation of any impurities. Using the minimum amount of material is desirable. Therefore, the ability to predict solubility and to …
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Path integral Monte Carlo simulations of solid H2 surfaces and thin 4He films on H2 substrates
… Path Integral Monte Carlo is a computational ab-initio method to calculate finite temperature equilibrium properties of quantum many-body systems. As input, only fundamental physical constants and pair-potentials are required. We carry out the first ab-initio particle simulations of three …
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Multinuclear magnetic resonance studies of proteins
… in this dissertation. We first studied fluorine labeled avian egg white lysozymes. Mutagenesis and other chemical modification methods were used to assign resonances from (4-F) Phe- and (4;F) Trp- hen egg white lysozyme. Next we used the fluorine labeled hen egg white lysozyme to probe the …
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New perspectives on ab initio calculation and physical insights gained through linkage to continuum theories
We explore the use of ab initio, density-functional methods for the study of large-scale materials problems. Three examples are presented: (i) the interplay of surface and edge reconstructions in long silicon nanowires, where we examine the effects on electrical and mechanical properties; (ii) the …
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Advances And Applications Of Static And Dynamic Correlation Methods In Ab-Initio Quantum Chemistry
Computational chemistry has made remarkable progress in the last couple of decades due to the availability of better and more powerful computers. However, there is definitely more room for improvement. There are problems in material science and biology that require 102 to 104 atoms to be considered …
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Quantenmechanische Berechnung der CD-Spektren von Cyclohexandionderivaten, Lactamen, Ribonuclease A sowie von Androstan-Bisporphyrinen
… is of special interest. Semiempirical and ab initio calculations were performed on cyclohexandione derivatives, bicyclic lactams, the protein Ribonuclease A and androstan-bisporphyrins. The objective for the smaller molecules was to predict the absolute configuration of the compounds by …
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Annotating and characterizing orphan gene in Zea mays via diverse RNA-Seq data
… remain significant limitation in our knowledge about orphan genes and their function. The traditional gene model prediction pipeline is based on the ab initio method and sequence homology, which is lacking for the orphan genes. It is hard to predict orphan genes by traditional methods. Moreover, …
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Beyond Color: Lattice Gauge Theory for Strongly-Coupled Physics
… this, it remains difficult to compute QCD observables because QCD is strongly-coupled, and typical perturbative methods used in QFT only work in specific regimes of validity for QCD. The most successful ab initio method to study QCD is Lattice Gauge Theory (LGT). This computational formalism …
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The design and development of GPU accelerated algorithms for ab initio integrals and integral derivatives illustrated on ab initio quantum and hybrid QM/MM dynamics
… Units (GPUs) are highly parallel, programmable accelerators boasting high peak floating point performance. Over the last couple of years the use of GPUs for general purpose computing have revolutionized quantum chemistry. The computational bottleneck in an ab-initio quantum method is the …