A Multireference Density Functional Approach to the Calculation of the Excited States of Uranium Ions

Author

Eric V. Beck

Date of Award

3-19-2007

Document Type

Dissertation

Degree Name

Doctor of Philosophy (PhD)

Department

Department of Engineering Physics

First Advisor

Larry Burgrraf, PhD

Abstract

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 ions and the uranyl (UO₂²⁺) ion showed the model achieved reductions in relative error with respect to Time Dependent Density Functional Theory (TDDFT) of 11-42%, with a corresponding reduction in computational effort in terms of MRCI expansion sizes of a factor of 25-64.

AFIT Designator

AFIT-DS-ENP-07-01

DTIC Accession Number

ADA466101

Recommended Citation

Beck, Eric V., "A Multireference Density Functional Approach to the Calculation of the Excited States of Uranium Ions" (2007). Theses and Dissertations. 2895.
https://scholar.afit.edu/etd/2895