The investigation of properties of atoms and molecules on surfaces is an increasing research area. On the one hand, there is an inherent scientific interest in chemical and physical properties of small structures of up to some thousand of atoms. On the other hand, these small structures have enormous technological importance, for instance in semiconductor industry and catalysis. For a controlled fabrication of nanostructures a detailed understanding of elementary surface processes of atoms and molecules as adsorption, desorption, diffusion, dissociation, and reaction is a prerequisite. The large scientific interest in artificial nanostructures is based on their novel physical and chemical properties.

The research group of Karina Morgenstern at the University of Hannover investigates the properties of atoms and molecules on metal surfaces in order to learn about their physical and chemical processes. The measurements are performed with scanning tunnelling microscopy (STM), which allows to image surfaces with atomic resolution in real space. Furthermore, the local density of states is measured in the first derivative of the tunnelling current (STS = scanning tunnelling spectroscopy). The second derivative of the tunnelling current gives chemical sensitivity and is used to identify the vibrational modes of single molecules in local vibrational spectroscopy (IETS = Inelastic Electron Tunnelling Spectroscopy).