Excitonic effects in a time-dependent density functional theory

摘要: Excited state properties of one-dimensional molecular materials are dominated by many-body interactions resulting in strongly bound confined excitons. These effects cannot be neglected or treated as a small perturbation and should appropriately accounted for electronic structure methodologies. We use adiabatic time-dependent density functional theory to investigate the organic semiconductors, conjugated polymers. Various commonly used functionals applied calculate lowest singlet triplet energies oscillator strengths poly(phenylenevinylene) ladder-type (poly)(para-phenylene) oligomers. Local approximations gradient-corrected describe excitonic states due lack an effective attractive Coulomb interaction between photoexcited electrons holes. In contrast, hybrid functionals, which include long-range nonlocal nonadiabatic corrections form fraction Hartree-Fock exchange, able reproduce effects. The finite exciton sizes dependent on amount orbital exchange included functional.