Date of Award

2017-01-01

Degree Name

Master of Science

Department

Physics

Advisor(s)

Tunna Baruah

Abstract

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.

Language

en

Provenance

Received from ProQuest

File Size

46 pages

File Format

application/pdf

Rights Holder

Sharmin Akter

Included in

Physics Commons

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