Regensburg 2010 – wissenschaftliches Programm
O 6.1: Vortrag
Montag, 22. März 2010, 11:15–11:30, H36
Phase boundaries in organic adlayers – a quantitative video-STM study — •Michael Roos, Harry E. Hoster, and R. Jürgen Behm — Institute of Surface Chemistry and Catalysis, Ulm University, D-89069 Ulm, Germany
Bis(terpyridine)derivatives (BTP) form highly ordered hydrogen-bonded networks on different substrates at solid surfaces [1,2]. Using time resolved scanning tunneling microscopy (STM), we have studied dynamic phenomena in such adlayers on Ag/Ru(0001) at room temperature. BTP molecules on Ag/Ru(0001) form coverage dependent networks with different hydrogen bonding configuration. At low coverages, a parallel chain structure (PCS) is formed in coexistence with a two-dimensional admolecule gas. At higher coverages, domains of a locally more densely packed quasi quadratic network (QQN) are formed . Time resolved STM imaging at QQN|PCS phase boundaries reveals a continuous exchange of molecules between both phases as indicative for a dynamic equilibrium. Based on a statistical evaluation of the STM sequences, we show that the anisotropy of the molecule-molecule interactions is not only reflected in the periodic structures of the 2 adlayers, but also in the probability of different types of local rearrangements at the phase boundary.
 M. Roos et al., Phys.Chem.Chem.Phys. 9, 2007, 5672.
H. E. Hoster et al., Langmuir 23, 2007, 11570.