title: Universal Exciton Size in Organic Polymers is Determined by Nonlocal Orbital Exchange in Time-Dependent Density Functional Theory.
abstract: 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.
authors.affiliation: Interdisciplinary Center for Scientific Computing, Ruprecht-Karls University , Im Neuenheimer Feld 205A, D-69120 Heidelberg, Germany.
authors.forename: Stefanie A
authors.identifier: http://orcid.org/0000-0002-6538-9876
authors.initials: SA
authors.lastname: Mewes
authors.affiliation: Institute for Theoretical Chemistry, Faculty of Chemistry, University of Vienna , Währingerstrasse 17, A-1090 Wien, Austria.
authors.forename: Felix
authors.identifier: http://orcid.org/0000-0003-0751-148X
authors.initials: F
authors.lastname: Plasser
authors.affiliation: Interdisciplinary Center for Scientific Computing, Ruprecht-Karls University , Im Neuenheimer Feld 205A, D-69120 Heidelberg, Germany.
authors.forename: Andreas
authors.identifier: http://orcid.org/0000-0002-5862-5113
authors.initials: A
authors.lastname: Dreuw