Regensburg 2013 – wissenschaftliches Programm
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DS: Fachverband Dünne Schichten
DS 32: Poster Session IV: Atomic layer deposition; Organic thin films; Organic Electronics and Phototovoltaics; Organic Materials for Spintronics - from spinterface to devices; Thin film photovoltaic materials and solar cells
DS 32.37: Poster
Donnerstag, 14. März 2013, 17:00–20:00, Poster B2
Comparative experimental and theoretical NEXAFS-study of Acenes and Azaacenes — •Michael Klues1, Klaus Hermann2, and Gregor Witte1 — 1Physics Department, Philipps Uni. Marburg, 35032 Marburg — 2Theory Department, Fritz Haber Institute, 14195 Berlin
NEXAFS is a powerful tool to investigate the electronic structure of molecules and can also be used to determine the molecular orientation. However, these analyses require a precise assignment of the occurring resonances, which can be provided by modern ab-initio DFT calculations implemented e.g. in the StoBe package [1]. In this study we have measured the C1s- and N1s NEXAFS signatures of various acenes (benzene and anthracene, pentacene), aza-acenes and their hydrogenated derivatives which were compared with StoBe-based calculations. By comparing spectra of acenes and aza-acenes, we carve out the influence of the higher core charge of nitrogen on the molecular electronic structure. While this effect is quite small, a distinct effect occurs upon hydrogenation of the aza-species because the conjugation of the pi-system is reduced so that the resulting signature can be described by a superposition of a dihydropyrazine and sideways attached small acenes. [1] K. Hermann, L.G.M. Pettersson, et al. Stobe-demon version 3.1. 2011