Physical Sciences and Mathematics Commons^™

Tethered Axial Coordination As A Control Modality In Rhodium(Ii)-Catalyzed Carbene Transfer Reactions, Anthony Dean Abshire

Doctoral Dissertations

Rhodium(II) paddlewheels are versatile carbene transfer catalyst that are broadly applied in insertion reactions, cycloadditions, and ylide transformations. The effects of axial coordination in rhodium(II)-catalyzed carbene transfer reactions are still little understood due to compounding factors that are difficult to isolate. Traditionally, researchers study axial coordination by addition of Lewis base additives. To ensure interaction between the Lewis base and catalyst, high molar equivalents are used. This can also have the undesired effect of hampering the activity of the catalyst and suppressing the yield of the reaction. We have developed ligands with a tethered Lewis base to overcome these issues. …

Theoretical Modeling Of Metallic Compounds With Versatile Properties By Combining First-Principles Calculations And Global Structure Prediction Algorithms, Jinseon Park

Doctoral Dissertations

Improving the target properties of existing materials or finding new materials with enhanced functionality for practical applications is at the heart of the materials research. In this respect, the first-principles approaches, which have been successfully integrated into modern high- performance computers, have become an indispensable part of the materials research, providing a better understanding of existing materials and guidance on the design of new materials. Using state-of-the-art computational/theoretical approaches that couple global structure prediction with ab initio density functional theory calculations, we investigate structural and electronic properties of Cs_xO [cesium oxides], Li_1+xMn₂O₄ [lithium …

Investigating The Properties Of Superfluid He-4 Through Density Functional Calculations, Matthew Francis Dutra

Doctoral Dissertations

We present a study of isotopically pure He-4 systems evaluated using helium density functional theory (He-DFT) with the intent of better understanding their ground state structural and energetic properties, particularly within the scope of singularly-doped helium droplets. We self-consistently solve for the density profiles and chemical potentials for a wide range of pure helium droplet sizes (up to 9500 atoms) via an imaginary time propagation method, and fit the resultant energetic data to a power law formula to be able to extrapolate values for even larger droplets. Subsequent calculations on singularly-doped droplets within the same size range yield accurate binding …

A Study Of The Optical And Negative Ion Properties Of Selected Chiral Molecules, Jason Michael Lambert

Doctoral Dissertations

Chirality is subtle geometric property where objects lack reflection plane symmetry. In this thesis I study three chiral molecules using a combination of experimental and theoretical methods to elucidate the relationships between conformation freedom, solvent choice, and temperature. The importance of nuclear motion when predicting the optical rotation is explored. For carvone, corrections with each nuclear mode coordinate is important. Predictions of the ORD have the incorrect sign without the inclusion of vibrational corrections. For the case of two newly synthesized amino acid derivatives the vibrational corrections did not correct the sign of the calculated ORD to bring it into …

Microscopic Description Of Nuclear Fission At Finite Temperature, Jordan David Mcdonnell

Doctoral Dissertations

While a predictive, microscopic theory of nuclear fission has been elusive, advances in computational techniques and in our understanding of nuclear structure are allowing us to make significant progress. Through nuclear energy density functional theory, we study the fission of thorium and uranium isotopes in detail. These nuclides have been thought to possess hyperdeformed isomers in the third minima of their potential energy surfaces, but microscopic theories tend to estimate either shallow or non- existent third minima in these nuclei. We seek an explanation in terms of neutron shell effects. We study how the fission pathways, the symmetry, and the …

Examination Of 4he Droplets And Droplets Containing Impurities At Zero Kelvin Using A Density Functional Approach, Ellen Brown

Masters Theses

Abstract

Detailed in this manuscript is a methodology to model ground state properties of ⁴He droplets at zero pressure and zero Kelvin using a density functional theory of liquid helium. The density functional approach examined here consists of two noted functionals from the literature and corresponding mean field definitions. A mean field and trial density are defined for each system and optimized to self-consistency using a matrix diagonalization technique. Initial calculations of planar slabs are performed and demonstrate reasonable agreement with experiment and with prior studies using density functional theory. Quantum properties of droplets and droplets containing atomic dopants …