Date of Award
Master of Science
Density Functional Theory (DFT) is one of the most successful and popular computational Quantum Mechanical approaches to understand materials. DFT allows the prediction of material properties from the electron density. Although in principle density functional theory is exact, it, however, relies on approximate functional for exchange-correlation energy. Due to the approximate nature of the exchange-correlation functional, the self-Coulomb energy of the electrons is not exactly canceled out by the self-exchange leading the spurious self-interaction error (SIE). This error is responsible for the unphysical orbital energies of DFT and delocalization of the orbitals. The orbital energies of the valence electrons are higher in DFT due to the self-interaction error. The SI correction leads to lower orbital energies and therefore the electronic density is less diffused. One of the properties where the SIE is seen is polarizability which is the response of a system to an applied electric field. We apply the recently developed Fermi-Lowdin orbital based self-interaction correction (FLOSIC) scheme to examine the polarizabilities of small molecules. We apply this method to ð???ð??? dimer, ð???ð???ð??¶ð???, and ð??¶6ð??»6 molecule along with ð???ð??? atom to calculate static dipole polarizability. For the Na atom, the calculated polarizability is in good agreement with experiment. For the molecules, more systems need to be studied to understand how SIC affects the calculated polarizability values.
Received from ProQuest
Akter, Sharmin, "Self-Interaction Corrected Polarizabilities Of Small Molecules" (2017). Open Access Theses & Dissertations. 398.