Isolated and deposited potassium clusters: Energetic and structural properties

With the ultimate purpose of studying the properties of potassium clusters deposited on a surface, we have at first studied the energetic and structural properties of isolated potassium clusters with up to 20 atoms. The global total-energy-minima structures have been determined by using the Density Functional Tight Binding method (DFTB) combined with genetic algorithms. For the isolated clusters in the gas phase we analyze the binding energy as well as the stability function. Moreover, structural similarity is studied using so-called similarity functions. Also the overall shape of the clusters and the radial distribution of the atoms are studied. Subsequently, we study the changes in the structure when these clusters are deposited on one out of two different potassium surfaces. Finally, the energy related to the deposition is studied in detail.