Universal exciton size in organic polymers is determined by nonlocal orbital exchange in time-dependent density functional theory
journal contributionposted on 2018-03-16, 13:25 authored by Stefanie A. Mewes, Felix PlasserFelix Plasser, Andreas Dreuw
© 2017 American Chemical Society. The exciton size of the lowest singlet excited state in a diverse set of organic π-conjugated polymers is studied and found to be a universal, system-independent quantity of approximately 7 Å in the single-chain picture. With time-dependent density functional theory (TDDFT), its value as well as the overall description of the exciton is almost exclusively governed by the amount of nonlocal orbital exchange. This is traced back to the lack of the Coulomb attraction between the electron and hole quasiparticles in pure TDDFT, which is reintroduced only with the admixture of nonlocal orbital exchange.
S.A.M. acknowledges funding of the Heidelberg Graduate School of Mathematical and Com- putational Methods for the Sciences (HGS MathComp) and Landesgraduiertenforderung Baden-Wurttemberg. F.P. acknowledges funding of the VSC Research Center funded by the Austrian Federal Ministry of Science, Research, and Economy (bmwfw).