Dresden 2009 – wissenschaftliches Programm
Bereiche | Tage | Auswahl | Suche | Downloads | Hilfe
O: Fachverband Oberflächenphysik
O 42: Poster Session II (Nanostructures at surfaces: arrays; Nanostructures at surfaces: Dots, particles, clusters; Nanostructures at surfaces: Other; Nanostructures at surfaces: Wires, tubes; Metal substrates: Adsorption of O and/or H; Metal substrates: Clean surfaces; Metal substrates: Adsorption of organic/bio moledules; Metal substrates: Solid-liquid interfaces; Metal substrates: Adsorption of inorganic molecules; Metal substrates: Epitaxy and growth; Heterogeneous catalysis; Surface chemical reactions; Ab-initio approaches to excitations in condensed matter; Organic, polymeric, biomolecular films– also with adsorbates; Particles and clusters)
O 42.64: Poster
Mittwoch, 25. März 2009, 17:45–20:30, P2
Structure-function relation in the photoswitch tetra-tert-butyl-azobenzene (TBA) on Au(111) — •Roland Schmidt1,2, Daniel Brete1,2, Sebastian Hagen2, Robert Carley1, Cornelius Gahl1, Petra Tegeder2, and Martin Weinelt1,2 — 1Max-Born-Institut, Berlin — 2Freie Universität-Berlin, Berlin
We have investigated tetra-tert-butyl-azobenzene (TBA) adsorbed on Au(111) by X-ray absorption (XAS) and autoionization spectroscopy at the Berlin synchrotron facility BESSY. In TBA the azobenzene photoswitch is decoupled from the substrate by four tert-butyl legs. XAS reveals a slight bending of the azo group of the trans isomer towards the Au(111) surface. The interaction of the N=N bond with the gold substrate is also reflected by an interchange of HOMO and HOMO-1, as identified from participator decay in Resonant-Raman-Auger. Autoionization of the C1s−1 π+1 excited state mainly occurs via spectator and participator decay, while the N1s−1 π+1 state shows an additional non-resonant Auger contribution of comparable strength. This demonstrates that charge transfer from the LUMO to the substrate is faster when exciting at the nitrogen edge and can explain the quite exceptional dependence of the TBA photoisometization yield on photon energy [1].
[1] S. Hagen, P. Kate, F. Leyssner, D. Nandi, M. Wolf, and P. Tegeder J. Chem. Phys. (2008), 129, 164102