Studies on Atomic and Molecular Properties Using Locally Scaled and Perdew-Zunger Self-Interaction Corrected Density Functional Approximations
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 formalism. The accuracy of electron density is examined by comparing moments of the density, ⟨rn ⟩ = ∫ 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 various 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.
Applied physics|Materials science
Oyedele, Philip A, "Studies on Atomic and Molecular Properties Using Locally Scaled and Perdew-Zunger Self-Interaction Corrected Density Functional Approximations" (2023). ETD Collection for University of Texas, El Paso. AAI30634989.