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Full-Text Articles in Computational Chemistry

Assessing Fixed-Node Diffusion Monte Carlo For Radical Polymerization Reaction Energetics, Timothy Brian Huber Jan 2024

Assessing Fixed-Node Diffusion Monte Carlo For Radical Polymerization Reaction Energetics, Timothy Brian Huber

Graduate Research Theses & Dissertations

The art of quantum chemistry is grounded to the discovery of a time efficient computational method that can capture the essential physics. Historically, the Hartree-Fock method, where an electron moves in the mean field of the other electrons, has provided the orbitals used to construct a single-reference Slater determinant and thus formed the basis for molecular orbital calculations. Kohn-Sham density functionals have become overwhelmingly popular among the chemistry community due to their low computational cost. However, their prediction of thermodynamic properties important in free radical polymerization has shown difficulty due to an artificial delocalization of electron density and spin contamination …


Computational Studies Of The Effects Of Substitutions On Silatranes And Ring Strain Energies, As Well As Determination Of Aromaticity And Complexation In Polypnictogen Analogues Of The Cyclooctatetraenyl Dianion, Alexander Stuart Pixler Jan 2023

Computational Studies Of The Effects Of Substitutions On Silatranes And Ring Strain Energies, As Well As Determination Of Aromaticity And Complexation In Polypnictogen Analogues Of The Cyclooctatetraenyl Dianion, Alexander Stuart Pixler

Graduate Research Theses & Dissertations

The work in this dissertation computationally examines four areas involving variations on archetype molecules and how they affect reactivity and physical properties. Studies in Chapters 2 and 3 assess substituent effects on cyclic systems, while those in Chapters 4 and 5 explore both partial and complete substitution of ring component atoms as well as the chemical implications of the substitution.The effect of substituents on molecular reactivity is a critical concept that affects every branch of chemistry. Previous work within our group showed that 1-hydridosilatrane was an effective and selective reducing agent for a variety of compounds. Fully 3,3,7,7,10,10-substituted silatranes have …


Structural Analysis Of Polar Aggregates And Inter-Ionic Distances In Room Temperature Ionic Liquids, Emily Elizabeth Dalbey Jan 2023

Structural Analysis Of Polar Aggregates And Inter-Ionic Distances In Room Temperature Ionic Liquids, Emily Elizabeth Dalbey

Graduate Research Theses & Dissertations

Ionic liquids have a wide variety of applications in chemistry due to their unique properties such as low flammability, low volatility, and high thermal and chemical stability. These properties make them great solvents, electrolytes for lithium-ion batteries, and more. Ionic liquids are salts whose components are mis-matched in size and shape leading to low melting points. To design an ionic liquid with a desired property it is key to first understand their structure. Lineshape analysis of the charge alternation peak from the experimentally measured or computationally calculated X-ray scattering data can give information about the size of the polar aggregates …


Tools For Understanding Static Structure Factors And Their Application To Simulations Of Liquids, Travis Mackoy Jan 2019

Tools For Understanding Static Structure Factors And Their Application To Simulations Of Liquids, Travis Mackoy

Graduate Research Theses & Dissertations

Molecular dynamics (MD) simulations can be used to compute static structure factors (��(��)) and provide an interpretation of the underlying periodic atomic ordering. MD simulations complement experimentally measured ��(��) by allowing qualitative assignment of peaks to various ordering, such as cation-anion ordering in ionic liquids, via decomposition of ��(��) into partial ��(��). Here we present a method for classifying interatomic distances that allows for quantitative peak assignment and visualization of atoms that contribute most to each peak in calculated ��(��) for soft materials. The method is illustrated by investigating ��(��) for the ionic liquid 1-butyl-1-methyl-pyrrolidinium bis(trifluoromethylsulfonyl)imide (C4C1pyrrTFSI), which shows two …