Date of Award

2022-12-01

Degree Name

Master of Science

Department

Physics

Advisor(s)

Mark R. Pederson

Abstract

Density functional theory - the most widely used theoretical method to study atoms,molecules, and solids - suffers from the well-known self-interaction error. A solution to the problem was suggested by Perdew and Zunger [1], who showed the self-interaction error can be removed with self-interaction correction. In 2014, Pederson showed a unitary transformation can be performed on the Kohn-Sham orbitals to generate Fermi-Löwdin orbitals which improve atomization energies, and avoid the computational costs of solving the localization equations.[2] This method is known as the Fermi-Löwdin Orbital Self-Interaction Correction (FLO-SIC). Until now, the FLO-SIC methodology has been used for atoms not containing f-electrons, because f-electrons were not implemented in the FLOSIC code, which is based on NRLMOL. This work presents an implementation of an f-electron capable NRLMOL including FLOSIC. Difficulties and strategies of FLOSIC with f-electrons are discussed, such as generating parameters known as Fermi-orbital descriptors used to define Fermi-Löwdin orbitals. Highest occupied molecular orbital energies are compared to experimental ionization potentials for several 6th row elements, which are particularly affected by self-interaction error. For some of the open shell elements, DFT predicts incorrect ground state valence configurations which can be recovered with FLOSIC. The results suggest that FLOSIC is a useful and efficient method to cure self-interaction error for systems containing f-electrons. Additionally, potential applications to molecular magnets are discussed, which are in dire need of an effective ab initio theory for accurate predictions.

Language

en

Provenance

Received from ProQuest

File Size

51 p.

File Format

application/pdf

Rights Holder

Alexander Irun Johnson

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Physics Commons

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