SKM 2021 – wissenschaftliches Programm

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CPP: Fachverband Chemische Physik und Polymerphysik

CPP 3: Polymer Physics

CPP 3.4: Hauptvortrag

Montag, 27. September 2021, 14:30–15:00, H3

Structural Transitions of Molecules on Surfaces — •Angelika Kühnle — Physical Chemistry I, Department of Chemistry, University Bielefeld, Universitätsstraße 25, 33615 Bielefeld, Germany

Molecular self-assembly constitutes a versatile strategy to create functional molecular structures at surfaces. Conventionally, self-assembly is associated with structures in thermodynamic equilibrium. In this talk, several examples will be given for molecular structures that are explained by thermodynamic equilibrium. However, observed structures might be kinetically trapped, and structural transitions can be induced by annealing. On the (111) surface of copper, dimolybdenum tetraacetate (MoMo) molecules are shown to undergo a reversible phase transition of molecular islands (2D solid phase) into mobile molecules (2D gas phase). Interestingly, while this phase transition is usually associate with heating, the mobilization of the MoMo molecules presented here is observed upon cooling. In this talk, the molecular-scale origin of this inverse phase transition is discussed.