Regensburg 2002 – scientific programme

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CPP: Chemische Physik und Polymerphysik

CPP 8: Neue Methoden II

CPP 8.4: Talk

Monday, March 11, 2002, 16:00–16:20, H39

Porphyrazine Compounds Studied by Resonant Photoemission — •Diana Pop, B. Winter, W. Freyer, R. Weber, D. Bröcker, T. Gießel, I. V. Hertel, and W. Widdra — Max-Born-Institut, Max-Born-Str. 2A, D-12489 Berlin

Besides their technological importance porphyrazine-based compounds containing a central metal atom are suitable systems for investigating the interactions between the metal atom and the surrounding organic ligand. Here we present results on photoemission experiments headed to systematically study the evolution of the electronic structure of Me-porphyrazines (Me=Cu, Zn) based materials in which the π electron system has been varied in a controlled manner by linear benzoannelation. We report photoemission measurements for four species. The smallest one is the standard porphyrazine, the next larger species contain 4, 8, 12 benzene rings, respectively. The experiments were performed at the MBI undulator beamline at BESSY II, using photon energies up to 135 eV. Changes of the electronic structure as a consequence of modified metal-ligand interactions for different ligand sizes are accessed by resonant photoemission and will be discussed for the Cu and Zn containing species. For the quantitative analysis reference measurements of the corresponding metal-free species have been used. It is shown that the strength of the resonance depends on the ligand size.