Ionization potentials and static dipole polarizabilities of polyacenes using Fermi-Lowdin self-interaction corrected density functional approximation

We study the static electric dipole polarizabilities and the first ionization potentials of polyacenes from benzene to pentacene using the Fermi-Lowdin Orbital based self-interaction corrected (FLOSIC) density functional method. Most common density functional approximations (DFA) that often accurately predict equilibrium properties show deviation from the piecewise exact linear behavior between integer electron numbers. These functionals favor fractional charges and cause excessive electron delocalization resulting in incorrect electron densities. Due to delocalization errors, the ionization potentials obtained using the LDA and PBE functionals rapidly decrease as a function of length. The application of the FLOSIC method shows that it corrects for this many-electron self-interaction error in ionization potentials of polyacenes. Furthermore, it is observed that the FLOSIC corrected electron density when used in simple LDA functionals results in a remarkably accurate prediction of the ionization potentials of polyacenes.