title: Site-dependence of van der Waals interaction explains exciton spectra of double-walled tubular J-aggregates.
abstract: The simulation of the optical properties of supramolecular aggregates requires the development of methods, which are able to treat a large number of coupled chromophores interacting with the environment. Since it is currently not possible to treat large systems by quantum chemistry, the Frenkel exciton model is a valuable alternative. In this work we show how the Frenkel exciton model can be extended in order to explain the excitonic spectra of a specific double-walled tubular dye aggregate explicitly taking into account dispersive energy shifts of ground and excited states due to van der Waals interaction with all surrounding molecules. The experimentally observed splitting is well explained by the site-dependent energy shift of molecules placed at the inner or outer side of the double-walled tube, respectively. Therefore we can conclude that inclusion of the site-dependent dispersive effect in the theoretical description of optical properties of nanoscaled dye aggregates is mandatory.
authors.affiliation: Institut für Chemie, Universität Potsdam, Karl-Liebknecht-Straße 24-25, D-14476 Potsdam, F. R. Germany. megow@uni-potsdam.de.
authors.forename: Jörg
authors.initials: J
authors.lastname: Megow
authors.forename: Merle I S
authors.initials: MI
authors.lastname: Röhr
authors.forename: Marcel
authors.initials: M
authors.lastname: Schmidt am Busch
authors.forename: Thomas
authors.initials: T
authors.lastname: Renger
authors.forename: Roland
authors.initials: R
authors.lastname: Mitrić
authors.forename: Stefan
authors.initials: S
authors.lastname: Kirstein
authors.forename: Jürgen P
authors.initials: JP
authors.lastname: Rabe
authors.forename: Volkhard
authors.initials: V
authors.lastname: May
mesh_terms: D002232:Carbocyanines / Q000737:chemistry; D005456:Fluorescent Dyes / Q000737:chemistry*; D000432:Methanol / Q000737:chemistry; D008968:Molecular Conformation; D056004:Molecular Dynamics Simulation; D013053:Spectrophotometry; D055672:Static Electricity; D014867:Water / Q000737:chemistry
chemical_list: D002232:Carbocyanines; D005456:Fluorescent Dyes; D014867:Water; D000432:Methanol