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Kinetics of Sulfur: Experimental Study of the Reaction of Atomic Sulfur with Acetylene and Theoretical Study of the Cn + So Potential Energy Surface

Description: The kinetics of the reaction of atomic sulfur with acetylene (S (3P) + C2H2) were investigated experimentally via the flash photolysis resonance fluorescence method, and the theoretical potential energy surface for the reaction CN + SO was modeled via the density functional and configuration interaction computational methods. Sulfur is of interest in modern chemistry due to its relevance in combustion and atmospheric chemistry, in the Claus process, in soot and diamond-film formation and in as… more
Date: May 2013
Creator: Ayling, Sean A.
Partner: UNT Libraries
open access

Computational Studies on Group 14 Elements (C, Si and Ge) in Organometallic and Biological Compounds.

Description: A series of computational studies were carried out on Group 14 (C, Si and Ge) elements in organometallic and biological compounds. Theoretical studies on classical and H-bridged A3H3+ (A=C, Si and Ge) as p ligands with different organometallic fragments at B3LYP and B3P86 level reveal a reverse charge transfer from ligand to metal in Si and Ge complexes whereas in C complexes there is a small charge transfer from metal to ligand. The H-bridged complexes are more stable than the complexes base… more
Date: May 2007
Creator: Yu, Liwen
Partner: UNT Libraries
open access

Kinetics and Mechanisms of Ligand Exchange Reactions of Chelate Complexes

Description: Certain ligand substitution reactions proceed to a complete displacement of the chelate ligand. Certain reactions proceed through a mechanism involving an initial fission of the tungsten-sulfur bond to afford a coordinatively-unsaturated intermediate which is rapidly attacked by chlorobenzene. The resulting solvated intermediate establishes an equilibrium which involves desolvation-solvation. Although main group organometallic chemistry has received a great deal of attention, this discussion wi… more
Date: May 1989
Creator: Cortés, José E. (José Enrique)
Partner: UNT Libraries
open access

Systematic Approaches to Predictive Computational Chemistry using the Correlation Consistent Basis Sets

Description: The development of the correlation consistent basis sets, cc-pVnZ (where n = D, T, Q, etc.) have allowed for the systematic elucidation of the intrinsic accuracy of ab initio quantum chemical methods. In density functional theory (DFT), where the cc-pVnZ basis sets are not necessarily optimal in their current form, the elucidation of the intrinsic accuracy of DFT methods cannot always be accomplished. This dissertation outlines investigations into the basis set requirements for DFT and how the … more
Date: May 2009
Creator: Prascher, Brian P.
Partner: UNT Libraries
open access

The One Electron Basis Set: Challenges in Wavefunction and Electron Density Calculations

Description: In the exploration of chemical systems through quantum mechanics, accurate treatment of the electron wavefunction, and the related electron density, is fundamental to extracting information concerning properties of a system. This work examines challenges in achieving accurate chemical information through manipulation of the one-electron basis set.
Date: May 2016
Creator: Mahler, Andrew
Partner: UNT Libraries
open access

Application of the Correlation Consistent Composite Approach to Biological Systems and Noncovalent Interactions

Description: Advances in computing capabilities have facilitated the application of quantum mechanical methods to increasingly larger and more complex chemical systems, including weakly interacting and biologically relevant species. One such ab initio-based composite methodology, the correlation consistent composite approach (ccCA), has been shown to be reliable for the prediction of enthalpies of formation and reaction energies of main group species in the gas phase to within 1 kcal mol-1, on average, of w… more
Date: May 2015
Creator: Riojas, Amanda G.
Partner: UNT Libraries
open access

Transition Metal Catalyzed Oxidative Cleavage of C-O Bond

Description: The focus of this thesis is on C-O bonds activation by transition metal atoms. Lignin is a potential alternative energy resource, but currently is an underused biomass species because of its highly branched structure. To aid in better understanding this species, the oxidative cleavage of the Cβ-O bond in an archetypal arylglycerol β-aryl ether (β–O–4 Linkage) model compound of lignin with late 3d, 4d, and 5d metals was investigated. Methoxyethane was utilized as a model molecule to study the ac… more
Date: May 2015
Creator: Wang, Jiaqi
Partner: UNT Libraries
open access

Knowledge Discovery of Nanotube Mechanical Properties With an Informatics-Molecular Dynamics Approach

Description: Carbon nanotubes (CNT) have unparalleled mechanical properties, spanning several orders of magnitude over both length and time scales. Computational and experimental results vary greatly, partly due to the multitude of variables. Coupling physics-based molecular dynamics (MD) with informatics methodologies is proposed to navigate the large problem space. The adaptive intermolecular reactive empirical bond order (AIREBO) is used to model short range, long range and torsional interactions. A … more
Date: May 2012
Creator: Borders, Tammie L.
Partner: UNT Libraries
open access

From Development of Semi-empirical Atomistic Potentials to Applications of Correlation Consistent Basis Sets

Description: The development of the semi-empirical atomistic potential called the embedded atom method (EAM) has allowed for the efficient modeling of solid-state environments, at a lower computational cost than afforded by density functional theory (DFT). This offers the capability of EAM to model the energetics of solid-state phases of varying coordination, including defects, such as vacancies and self-interstitials. This dissertation highlights the development and application of two EAMs: a Ti potential … more
Date: May 2014
Creator: Gibson, Joshua S.
Partner: UNT Libraries
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