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Full-Text Articles in Physics
Quantum-Mechanical Evaluation Of Defects In Uranium-Bearing Materials, Megan Hoover
Quantum-Mechanical Evaluation Of Defects In Uranium-Bearing Materials, Megan Hoover
All Dissertations
Quantum-mechanical calculations using density functional theory with the generalized gradient approximation were employed to investigate the effects dopants have on the uranium dioxide (UO2) structure. Uraninite is a common U4+ mineral in the Earth's crust and an important material used to produce energy and medical isotopes. Though the incorporation mechanism remains unclear, divalent cations are known to incorporate into the uranium dioxide system. Three charge-balancing mechanisms were evaluated to achieve a net neutral system, including the substitution of (1) a divalent cation for a tetravalent uranium atom and oxygen atom; (2) two divalent cations for a tetravalent …
Building Predictive Chemistry Models, Christopher Browne, Nicolas Onofrio, Alejandro Strachan
Building Predictive Chemistry Models, Christopher Browne, Nicolas Onofrio, Alejandro Strachan
The Summer Undergraduate Research Fellowship (SURF) Symposium
Density Functional Theory (DFT) simulations allow for sophisticated modeling of chemical interactions, but the extreme computational cost makes it inviable for large scale applications. Molecular dynamics models, specifically ReaxFF, can model much larger simulations with greater speed, but with lesser accuracy. The accuracy of ReaxFF can be improved by comparing predictions of both methods and tuning ReaxFF’s parameters. Molecular capabilities of ReaxFF were gauged by simulating copper complexes in water over a 200 ps range, and comparing energy predictions against ReaxFF. To gauge solid state capabilities, volumetric strain was applied to simulated copper bulk and the strain response functions used …