Nanoclusters to nanotubes: An ab initio study

The electronic and geometric structure properties of silicon-carbide SimCn nanoclusters have been studied within the local density approximation to density functional theory (LDA-DFT) with Slater-Vosko-Wilk-Nussair (SVWN) exchange-correlation functional. One of the primary goals of this work is to determine how the structures, bonding and relative stabilities of the clusters are affected by size and stoichiometry. Detailed results are presented on the isomeric energy level differences, binding energies, bond dissociation energies and reaction pathways for the neutral and the charged species. The stability of the clusters varies with the ratio of the number of silicon to carbon atoms in the cluster. Clusters with equal numbers of silicon and carbon atoms are found to be particularly stable. In particular, Si3C3 cluster was found to be a candidate for a highly stable or a so-called "magic cluster". In contrast to the neutral clusters, cationic clusters appear to prefer more open-ended structures and ionization led to a decrease in dimensionality. (Abstract shortened by UMI.).