"RESonant PhotoElectron Diffraction (RESPED) a tool for surface science studies"
Présenté par
Dr Alberto Verdini (Curriculum vitae)
After graduating in Physics “Laurea cum laude” at the University of Perugia (Italy), discussing the thesis "Studio delle proprieta' elastiche dei superreticoli a semiconduttore mediante spettroscopia Brillouin", he moved to Trieste, where he joined as phd student the research group led by prof. F. Tommasini.
From 2001 he is beamline scientist at the ALOISA beamline, and from summer 2019 he moved to Perugia, where he run a joint Laboratory together with the collegues of the Dept of Physics and Geology.
He's main research activity is the study of the growth and of the electronic, structural and magnetic properties of surfaces and thin films (organic and inorganic), deposited on different metals and semiconductors, such as for example the growth of Fe on Cu3Au(001), Cu(110), Cu(111), Ag(001), the growth and the electronic properties of thiols, polyacenes, and metal-organic molecules (tetrapyrroles, metal-free or metalated, such as phtalocyanines and porphyrins) on different substrates, such as Cu(111), Au(110), Si(100), Ag(100), Au(111), Pd(100), and prexidized surface metals (Cu(111, Cu(110, Pd(100)).
Abstract:
A layout of the resonant photoelectron diffraction technique, RESPED, is described from the theoretical basis to the data acquisition and analysis procedures. RESPED relies on the chemical sensitivity of photoemission, with the possibility to further enhance this sensitivity by working at the absorption edge of a selected atom. Moreover, the photoemitted electrons undergo scattering from the neighboring atoms (photoelectron diffraction, PED), providing information on the structure around the selected emitting atom. Here we present the concepts of photoemission and electron diffraction and how to exploit them together with the X-ray absorption to study particular systems. A few representative applications are presented, where RESPED is shown to overcome some limitations of conventional PED thanks to the possibility of enhancing the signal of low concentration species, providing a chemical selectivity in the valence band, and discriminating the contribution from atoms of the same species, but in different structural environments or valence state.