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O: Fachverband Oberflächenphysik

O 41: Metal Substrates: Adsorption II

O 41.1: Vortrag

Mittwoch, 28. März 2007, 15:45–16:00, H39

Controllable molecular registration state in self-assembly of 3(5)-(9-anthryl) pyrazole molecule on Ag(111) — •Ruifen Dou¹, Arno Tilkorn¹, Dingyong Zhong¹, Wenchong Wang¹, Yue Wang², Lifeng Chi¹, and Harald Fuchs¹ — ¹Physikalisches Institut, Universitaet Muenster, 48149 Muenster, Germany — ²Key Laboratory for Supramolecular Structure and Materials of Ministry of Education, Jilin University, Changchun 130012, China

The highly-ordered molecular structures of 3(5)-(9-anthryl) pyrazole (ANP) have been investigated on Ag(111) by low-energy electron diffraction (LEED) and scanning tunneling microscopy (STM). Through tailoring film preparation, two different superstructures, α and β, corresponding to two different molecular registration states have been obtained on Ag(111). At the low substrate temperature (229 K), the structure α can be prepared, in which the ANP molecule is adsorbed the surface with the anthryl-group plane tilting in respect to the substrate surface. After annealing the sample to room temperature, it is found that the structure α gradually evolves into the structure β with four molecules bound together through the hydrogen bonds among them and the anthryl-group plane parallel to the substrate surface to compromise to forming hydrogen bonds. Our analysis reveals a fact that the adsorbate-substrate interaction dominated in the structure α can change into the hydrogen-bonds prevailed over the structure β as mediating the growth temperature, which is responsible for the variation in the molecular registration states from the anthryl-group plane tilting with the substrate surface to parallel to surface.