Molecular Orbital Interpretation of Magic Clusters with Non-Magic Numbers

Exploring water adsorption and reactivity in a series of doped aluminum cluster anions

We present a systematic density functional study of central- and surface-doped aluminum cluster anions Al₁₂X^- (X = Mg, B, Ga, Si, P, Sc-Zn), their interactions and reactivity with water. Adsorption of water molecules on central-doped clusters is governed by the cluster electron affinity. Doping introduces a dramatic change in the cluster electronic structure by virtue of different ordering and occupation of super-atomic shells, which leads to the creation of complementary active sites controlling the reactivity with water. Surface doping creates unequal charge distribution on the cluster surface, resulting in the adsorption and reactivity of surface-doped clusters being dominated by electrostatic effects. These results demonstrate the strong influence of the doping position on the nature of the interaction and reactivity of the cluster, and contribute to a better understanding of doping effects.

Computational cogitation of Cn@Al12 clusters

A variety of novel Cn Al12 core-shell nanoclusters have been investigated using density functional calculations. A series of Cn cores (n=1-4) have been encapsulated by icosahedral Al12 , with characteristic physical properties (energetics and stabilities, ionisation energies, electron affinities) calculated for each cluster. Other isomers, with the Cn moiety bound externally to the Al12 shell, have also been studied. For both series, a peak in stability was found for n(C)=2, a characteristic that appears to be inextricably linked with the relaxation of the constituent parts upon dissociation. Analysis of trends for ionisation energies and electron affinities includes evaluation of contributions from the carbon and aluminium components, which highlights the effects of composition and morphology on cluster properties.