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Nuclear Engineering

Air Force Institute of Technology

Density functionals

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Full-Text Articles in Engineering

A Multireference Density Functional Approach To The Calculation Of The Excited States Of Uranium Ions, Eric V. Beck Mar 2007

A Multireference Density Functional Approach To The Calculation Of The Excited States Of Uranium Ions, Eric V. Beck

Theses and Dissertations

An accurate and efficient hybrid Density Functional Theory (DFT)/Multireference Configuration Interaction (MRCI) model for computing electronic excitation energies in heavy element atoms and molecules was developed. This model incorporated relativistic effects essential for accurate qualitative and quantitative spectroscopic predictions on heavy elements, while simultaneously removing spin-multiplicity limitations inherent in the original model on which it is based. This model was used to successfully compute ground and low-lying electronic states for atoms in the first two rows of the period table, which were used for calibration. Once calibrated, calculations on carbon monoxide, bromine fluoride, the bromine atom, uranium +4 and +5 …


Excited States Of Silicon Carbide Clusters By Time Dependent Density Functional Theory, John E. Boyd Jun 2004

Excited States Of Silicon Carbide Clusters By Time Dependent Density Functional Theory, John E. Boyd

Theses and Dissertations

Previous AFIT research with density functional theory (DFT) has shown itself to be accurate for small SimCn (m,n ≤ 5) clusters at a fraction of the cost of other quantum mechanical methods, but it is only a ground state theory. Time dependent density functional theory (TDDFT), however, is able to calculate excited states as well. Evaluating the accuracy of these methods with respect to the excited states of these clusters was the focus of this research, specifically with respect to the excitation energies, geometries, and vibrational frequencies. It is shown that for the excited states that can …