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MO: Fachverband Molekülphysik

MO 24: Elektronische Spektroskopie

MO 24.7: Talk

Friday, March 6, 2009, 12:15–12:30, VMP 6 HS-G

Guidance or misguidance: photoelectron spectra of organic semiconductors from density functional theory — •Stephan Kümmel and Thomas Körzdörfer — Theoretische Physik, Universität Bayreuth, D-95445 Bayreuth

Eigenvalues from density functional theory (DFT) are frequently used to help in the interpretation of photoelectron spectra. This practice can be very successful or quite misguiding, depending on the "performance" of DFT for the particular system at hand. Especially for organic semi-conductors like PTCDA, standard density functionals cannot explain the measured spectra. So far, little explanation has been offered for when DFT "works" and when it does not. We demonstrate that electronic self-interaction plays a decisive role for the reliability of the eigenvalue spectrum and present a self-interaction free approach which leads to realistic spectra also for the difficult cases of organic semiconductors.