Dresden 2017 – wissenschaftliches Programm
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O: Fachverband Oberflächenphysik
O 88: Electronic Structure Theory: New Concepts and Developments in Density Functional Theory and Beyond - VI
O 88.4: Vortrag
Donnerstag, 23. März 2017, 11:15–11:30, GER 38
Electronic structure and solid-state optical properties of indigo from time-dependent optimally tuned range-separated hybrid functional theory — •Bernd Kollmann1, Arun Kumar Manna2, Daniel Lüftner1, Leeor Kronik2, and Peter Puschnig1 — 1Institute of Physics, NAWI Graz, University of Graz, Austria — 2Department of Materials and Interfaces, Weizmann Institute of Science, Israel
Indigo is a natural dye with a long history in organic chemistry. Recent applications of indigo as a functional building block for organic electronics, like in solar cells or field effect transistors, have renewed the interest in the chemical and physical properties of this molecule. We report on its electronic structure for the isolated molecule as well as for the alpha- and beta- bulk molecular crystal phases. Further we investigate the optical properties of the bulk molecular crystal phases. For the molecule we employ an optimally tuned range-separated hybrid functional (OT-RSH) within density functional theory. Comparing the theoretical results obtained with different levels of theory and with experiment emphasizes the need for going beyond simple semi-local DFT-functionals in order to obtain the correct orbital ordering. For the bulk crystals we take into account the screening in the bulk by using an optimally tuned screened range-separated hybrid (OT-SRSH) approach. Regarding the optical properties of the bulk molecular phases we employ time-dependent density functional theory (TDDFT) to calculate the absorption spectra, whereby TDDFT represents an accurate low-cost substitute to many-body perturbation theory.