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An experimental and theoretical study on the structure and energetics of stellated gold clusters at several sizes is presented. Systematic molecular dynamics simulations on Kepler-Poisont classified clusters are performed based on cuboctahedral and icosahedral cores, following present and previous studies that suggest that stellated clusters grew from these seeds. For cluster sizes up to 10802 atoms, full atomistic molecular dynamics simulations at room temperature have been carried out. Results show that stellated clusters in the bigger size regime maintain their star-like shape at room temperature, and by means of linear fitting of energy data to proper function models, it is predicted that the two types of stellated structures might coexist at room temperature for relatively large sizes, these findings being in good agreement with experimental results.

The structural and electronic properties of clusters of up to 7 crosslinked C 60 molecules are calculated at the semiempirical AM1 and PM3 levels within the linear scaling divide and conquer scheme ͑DCM͒ of Yang. An uniaxial contraction of ϳ1.2% along the c ជ direction of the monomer C 60 due to the polymerization is found through our geometry optimization procedure with no symmetry restrictions. The clustering formation of four C 60 through the suggested ͓2ϩ2͔ cycloaddition mechanism is a very favorable event, which is consistent with other theoretical results. HOMO-LUMO gap energies decrease as the cluster size increases, predicting the possible onset of conductor behavior as size increases. Our results are in agreement with the two-dimensional C 60 polymer model proposed by Oszlanyi and Forro. The usefulness of the DCM to study these materials is shown.

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Nanoparticle research disciplines—chemical synthesis, applied physics and devices based on their physical-chemical properties, and computational physics—have been very active fields for the last 15 years or so, because of the potential and current applications in medicine, catalysis, energy storage, environment and electronics applications. This wide spectrum of disciplines and their applications keep metallic nanoparticles as one of the most promising nanostructures and their research as one of the cornerstones of nanotechnology. In this contribution we present a comprehensive and extended geometrical description for the most common shapes and structures for metallic nanoparticles, as well as experimental results for these geometries with some variations given by truncations.