Structure Determination of Small Metal Clusters by Density-Functional Theory and Comparison with Experimental Far-Infrared Spectra

Small metal clusters or nano-particles exhibit properties that are often quite different from those in the bulk phase. For example, small metal clusters have been shown to exhibit unusual magnetic properties. Small nanoparticles also play an increasingly important role in catalysis. Therefore, it is paramount to gain a better understanding of the atomic structure and properties of small metal clusters. The size-specific far-infrared vibrational spectra for charged vanadium clusters as well as charged and neutral niobium clusters with sizes between 3 and 24 atoms have been measured using infrared multiple photon dissociation. Using DFT calculations, we calculated the ground state energy and vibrational spectra for a large number of stable and unstable geometries of such clusters. Comparison of the calculated vibrational spectra with those obtained in the experiment allows us to deduce the cluster size specific atomic structures.