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Abstract: We report a systematic trend in the structural evolution of Pt n clusters based on the first principle calculation. We show that up to n =9, Pt n clusters favor planar geometries and a structural transition to non-planar geometries occur at n =10, which further evolves into cubic structures for larger clusters. Based on the stability analysis, it is found that n =6 and 10 are more stable than others. The bonding analysis showed that an enhanced p-orbital contribution causes the structural transition from two to three dimensional geometries. [Copyright &y& Elsevier]

Abstract: In this work we demonstrate the influence of an impurity atom in tuning the stability of Pb13 cluster. For this purpose we have investigated the electronic and geometric structure of MPb12 (M=Pb, C, Al, Mg) clusters using the ab initio molecular dynamics simulation method. The energy gap between the highest occupied and lowest unoccupied energy levels of Pb13 and MgPb12 is estimated to be 0.95 and 2.3eV, respectively. The significant increase in the energy gap is resulted from the energy level reordering of Pb13 by the incorporation of Mg atom. Further investigations of the stability of MPb12 clusters reveal that the interplay between the atomic and electronic structure is crucial to understand the stability of small size clusters. [Copyright &y& Elsevier]

The interaction of water with wide band gap metal oxides has wide ranging applications. Using first principles approach we demonstrate that a mixed oxide of Sn x Ti 1− x O 2 ( x = 0.5) significantly reduces the dissociation barrier of water in comparison to SnO 2 and TiO 2 surfaces. From the charge distribution at the top layer it is seen that Sn x Ti 1− x O 2 is more polar, where the charge separation between metal and oxygen atoms is more than SnO 2 and TiO 2 surfaces. The reason behind higher activity of the mixed surface has been explained by the surface morphology and larger surface charge density at the top layer. [ABSTRACT FROM AUTHOR]

Abstract: We present results of our theoretical calculation on structural and electronic properties of passivated rutile (TiO2) n quantum dots as a function of the size of the dots. Structural properties viz. geometry, bond lengths, binding energies and electronic properties such as HOMO–LUMO gap, density of states and HOMO, LUMO densities have been analyzed. The passivation of surface Ti with –OH groups and surface O atoms with –H atoms increases the HOMO–LUMO energy gap of the clusters. Our study reveals that the HOMO densities for rutile quantum dots are delocalized throughout the whole cluster while that of LUMO are strongly localized on a few surface Ti atoms. [Copyright &y& Elsevier]