Date of Award


Degree Name

Master of Science




Mark R. Pederson

Second Advisor

Koblar A. Jackson


The configuration interaction (CI) methods is an exact method to solve the non relativistic Schrodinger equation, describing the wave function as a linear combination of Slater determinants. Because the computation time grows factorially as the number of electrons, CI is mostly used for relatively small systems. Density functional theory (DFT) rose as one of the most used methods for computational quantum chemistry in the last 30 years. DFT can describe a system's properties with the electron density, which only depends of of three coordinates. Due to its low computational costs it allows one to study bigger systems than CI, however it does not have the same accuracy as the former.In this work we present a methodology to calculate the overlap between electron configurations that have different Kohn-Sham orbitals (KSO), where the KSO obtained from DFT are used to build Slater determinants, and the overlap of these is calculated as in CI. The overlap tool application is shown in the study of three different dimers, \ce{H2}, \ce{N2}, and \ce{Cr2}, to review the collapse phenomena of a polarized electron density into an indistinguishable unpolarized state. Our results show how the collapse of a polarized state into an unpolarized solution does not require a complete overlap.




Recieved from ProQuest

File Size


File Format


Rights Holder

Jose Gustavo Bravo Flores

Included in

Physics Commons