Date of Award
Master of Science
This thesis examines some properties of atoms and molecules using one-electron self-interaction-correction (SIC) methods such as the Perdew-Zunger SIC (PZSIC) and the locally scaled SIC method of Zope and coworkers within the Fermi-Lowdin SIC formal- ism. The accuracy of electron density is examined by comparing moments of the den- sity, ⟨r^n⟩ = ∫ ρ(r)rndτ = ∫ ∞ 0 4πr2ρ(r)rndr (n = −2, −1, 0, 1, 2, 3) with the corresponding available values from the Coupled cluster (CC) singles, doubles, and perturbative triples (CCSD(T)) method. Three test sets are considered: boron through neon neutral atoms, two and four electron cations, and 3d transition metals. Each set was tested with PBE, LDA, PZSIC-PBE, and PZSIC-LSDA functionals using default-NRLMOL basis, aug-cc- pwcvtz, and aug-cc-pwcvqz basis sets. Results show that for the transition metals, PBE and LDA with default basis have smaller deviations compared to PZSIC-PBE and PZSIC- LSDA. The second part of the thesis examines the possibility of obtaining good energetics by perturbatively applying the SIC to the energy using the self-consistent density of var- ious density functionals as well as the Hartree-Fock approximation(s). Such an approach provides significantly improved barrier heights compared to uncorrected DFAs. Our results show that the LSIC method [Zope et al., J. Chem. Phys. 151, 214108 (2019)] consistently performs better than the PZSIC method. This preliminary work suggests such an approach can be useful for certain properties.
Recieved from ProQuest
Philip Adeniyi Oyedele
Oyedele, Philip Adeniyi, "Studies On Atomic And Molecular Properties Using Locally Scaled And Perdew-Zunger Self-Interaction Corrected Density Functional Approximations" (2023). Open Access Theses & Dissertations. 3931.