Poster

High resolution electron energy loss spectroscopy of Pd- and Pt-phthalocyanine on Ag(111)

J. Sforzini^1,2, F. C. Bocquet^1,2, and F. S. Tautz^1,2

¹Peter Gruenberg Institut (PGI-3), Forschungszentrum Juelich, 52425 Juelich, Germany

²Juelich Aachen Research Alliance (JARA), Fundamentals of Future Information Technology, 52425 Juelich, Germany

We investigated the geometrical and the vibrational properties of Pd- and Pt-Phthalocyanine on Ag(111) by Low Energy Electron Diffraction (LEED) and by High Resolution Electron Energy Loss Spectroscopy (HREELS). The LEED patterns show that the molecules grow highly ordered on the surface. The HREELS spectrum is dominated by vibrational modes with symmetry A_2u, that producing an out-of-plane variation in the dipole moment, indicates a flat geometry adsorption. The asymmetric vibrational losses, between 1000 and 1500 cm^-1 indicates the presence of an interfacial dynamical charge transfer molecule-substrate, more predominant in the case of Pd molecules. We also studied the systems after molecular hydrogen exposure observing no drastically changes in the behavior with the central metal type.