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CPM SeminarSupramolecular self-assembly of organic molecules on bare and patterned metal surfacesGiovanni CostantiniMax-Planck-Institut für FestkörperforschungThe deposition and self-organization of small organic molecules on single crystal metal substrates is studied by means of in-situ ultrahigh vacuum variable temperature STM. Trimesic acid (TMA) is taken as a prototypical example for studying the formation of supramolecular architectures that depend on the interaction of the molecules with the substrate and among each other. In particular it is shown how, by carefully choosing the deposition conditions, it is possible to influence the charge status of TMA and therefore to switch between the formation of hydrogen-bonded and coordination-bonded structures. The role of the substrate symmetry is clarified by depositing TMA both on Cu (110) and Cu(001). While it has almost no importance for the hydrogen-bonded networks, it becomes determinant for the metal-organic complexes: linear chains of alternating TMA and Cu atoms are formed on Cu(110) but compact, rosette-like arrangements with a central Cu atom are found on Cu(001). The real-space structures of these supramolecular aggregates are elucidated at the molecular scale and the comparison with preliminary ab-initio DFT calculations is discussed.One-dimensional nanotemplates with tunable periodicity were also produced by exposing the Cu(110) surface to oxygen. The preferential binding of organic molecules to pure metal substrates, transforms this nanotemplate into a periodic striped confining potential for the adsorption of TMA.
Thursday, November 27th 2003, 15:30
Ernest Rutherford Physics Building, R.E. Bell Conference room (room 103) |