Probing structure, electronic property, and hydrogen adsorption for the alkali auride series

. The structural evolution, relative stability, electronic property, and hydrogen adsorption of the alkali auride series, Au n M ( n = 1 - 8 ), M = Li , Na, K, Rb, Cs), have been investigated using the density functional theory calculations at PW91 level. For the lowest-energy clusters, the dopant atom M prefers to occupy a peripheral or capped site in the host, and M-induced geometries become three-dimensional more easily. The average binding energy per atom, fragmentation energy, second-order difference of energy, and HOMO-LUMO energy gap show a pronounced odd-even oscillation with the number of Au atoms, and the enhanced relative stabilities are found in Au 5 M ( M = Li , Na, K) and Au 3 M ( M = Rb , Cs) clusters. In these clusters, the H 2 molecule would like to bond with Au atom rather than impurity atom. After adsorption, the Au n M structures and H 2 molecule in all Au n M-H 2 clusters are hardly perturbed and still maintain their structural integrity. The geometrical and energetic information indicates a weak adsorption of H 2 molecule.