From clusters to the solid state: Global minimum structures for cesium clusters Csn (n=2-20,∞) and their electronic properties

A systematic search for the global minimum structures of neutral cesium clusters with up to 20 atoms is performed utilizing a density-based genetic algorithm within density-functional theory in a scalar-relativistic pseudopotential formalism. The transition from two- to three-dimensional structures is found to be ambiguous and no unique growth pattern could be identified. Previously proposed icosahedral structure growth could not be verified within this size regime. Using a calibrated static dipole polarizability for atomic cesium to density functionals, the evolution of this property with increasing cluster size is discussed and compared to other alkali-metal clusters. For each cluster size, electronic properties are calculated and compared to available experimental data, and the extrapolation to the bulk limit is discussed.