Dresden 2014 – wissenschaftliches Programm
Bereiche | Tage | Auswahl | Suche | Aktualisierungen | Downloads | Hilfe
DS: Fachverband Dünne Schichten
DS 43: Poster II: Organic thin films; Atomic layer deposition, Thin film characterization: Structure analysis and composition (XRD, TEM, XPS, SIMS, RBS, ...)
DS 43.12: Poster
Donnerstag, 3. April 2014, 16:00–19:00, P1
Theoretical analysis of the Anthracene NEXAFS signature — •Michael Klues1, Klaus Hermann2, and Gregor Witte1 — 1Physics Department, Phillipps Uni. Marburg, 35032 Marburg — 2Theory Department, Fritz Haber Institute, 14195 Berlin
NEXAFS is a powerful technique that is experiencing a renewed interest owing to the recent success in the field of organic electronics, as it provides detailed information on electronic properties and orientational ordering in such molecular materials. However, to fully exploit the potential of this technique, a precise and reliable identification and assignment of spectral features within the NEXAFS spectra is needed. In the present work, we have calculated the NEXAFS spectra of Anthracene in the frame of density functional theory by using the StoBe code. Comparison to experimental data shows excellent agreement and points out the high precision StoBe reaches in predicting energies of excitations with errors less than 300meV. The key to such accurate values without any subsequent, empirical energy shift is to handle excited electronic configurations. By matching spectra resulting from excited states with different localized excitation centers we carve out the influence of chemical shifts and core hole effects. Furthermore it is possible to label the numerous resonances occurring in the NEXAFS spectrum. The detailed calculation also enables a visualization of final states like for example Rydberg states using the fully relaxed excited electronic structure. These illustrations point out the influence of initial and final states on the intensity and energetic shift of the individual partial NEXAFS resonances of the various excitation centers.