title: Estimating excitonic effects in the absorption spectra of solids: problems and insight from a guided iteration scheme.
abstract: A major obstacle for computing optical spectra of solids is the lack of reliable approximations for capturing excitonic effects within time-dependent density functional theory. We show that the accurate prediction of strongly bound electron-hole pairs within this framework using simple approximations is still a challenge and that available promising results have to be revisited. Deriving a set of analytical formulas we analyze and explain the difficulties. We deduce an alternative approximation from an iterative scheme guided by previously available knowledge, significantly improving the description of exciton binding energies. Finally, we show how one can "read" exciton binding energies from spectra determined in the random phase approximation, without any further calculation.
authors.affiliation: Humboldt-Universität zu Berlin, Institut für Physik and IRIS Adlershof, 12489 Berlin, Germany.|European Theoretical Spectroscopy Facility (ETSF).
authors.forename: Santiago
authors.initials: S
authors.lastname: Rigamonti
authors.affiliation: European Theoretical Spectroscopy Facility (ETSF).|Institut Lumière Matière, UMR5306 Université Lyon 1-CNRS, Université de Lyon, F-69622 Villeurbanne Cedex, France.|Friedrich-Schiller Universität Jena, Institut für Festkörpertheorie und -optik, Max-Wien-Platz 1, 07743 Jena, Germany.
authors.forename: Silvana
authors.initials: S
authors.lastname: Botti
authors.affiliation: European Theoretical Spectroscopy Facility (ETSF).|Laboratoire des Solides Irradiés, École Polytechnique, CNRS, CEA-DSM, F-91128 Palaiseau, France.
authors.forename: Valérie
authors.initials: V
authors.lastname: Veniard
authors.affiliation: Humboldt-Universität zu Berlin, Institut für Physik and IRIS Adlershof, 12489 Berlin, Germany.|European Theoretical Spectroscopy Facility (ETSF).
authors.forename: Claudia
authors.initials: C
authors.lastname: Draxl
authors.affiliation: European Theoretical Spectroscopy Facility (ETSF).|Laboratoire des Solides Irradiés, École Polytechnique, CNRS, CEA-DSM, F-91128 Palaiseau, France.
authors.forename: Lucia
authors.initials: L
authors.lastname: Reining
authors.affiliation: European Theoretical Spectroscopy Facility (ETSF).|Laboratoire des Solides Irradiés, École Polytechnique, CNRS, CEA-DSM, F-91128 Palaiseau, France.
authors.forename: Francesco
authors.initials: F
authors.lastname: Sottile