Role of hydrogen in dimerizaton of aluminum clusters: a theoretical study.

We have used density functional theory to investigate how Al(13) cluster dimers can be formed with or without a bridging hydrogen. We have identified several stable dimers in which 0, 1, or 2 hydrogen atoms link two bare clusters together. Each of these structures can adsorb further H atoms in atop sites on the surface of the dimer.

DFT study of H adsorption on magnesium-doped aluminum clusters.

In this study we use density functional theory (DFT) to investigate the properties and H adsorption characteristics of structural isomers of the magnesium-doped aluminum cluster, Al(12)Mg. Our results show that the exohedral structure (exo-MgAl(12)) is significantly lower in energy (1.59 eV) than the endohedral structure (endo-Al(12)Mg); however, the exohedral structure shows significant structural distortion.

First principles investigation of H addition and abstraction reactions on doped aluminum clusters.

We have investigated axial interactions of H(2) with Al(12)X (X = Mg, Al, and Si) clusters and found that homolytic dissociation leading to Al(12)XH and H atom proceeds without a barrier but is an extremely endothermic process. The calculated difference in energy of the addition and abstraction reactions indicates that any Al(12)X-based hydrogen storage technology that involves predissociation of H(2) will be limited by the competing processes. We have also discovered that while there is a modest barrier for dissociation of H(2) on a single Al(12)Mg cluster to give the dihydride, the process occurs spontaneously between two closely spaced Al(12)Mg clusters, resulting in the formation of two Al(12)MgH species.

Performance of numerical basis set DFT for aluminum clusters.

We have investigated and compared the ability of numerical and Gaussian-type basis sets combined with density functional theory (DFT) to accurately describe the geometries, binding energies, and electronic properties of aluminum clusters, Al12XHn (X = Al, Si; n = 0, 1, 2). DFT results are compared against high-level benchmark calculations and experimental data where available. Properties compared include geometries, binding energies, ionization potentials, electron affinities, and HOMO-LUMO gaps.