Probing structure, electronic property, and hydrogen adsorption for the alkali auride series
School of Science, East China University of Technology, 330013, Nanchang, China
2 Software college, East China University of Technology, 330013, Nanchang, China
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Accepted: 2 March 2017
Published online: 10 April 2017
The structural evolution, relative stability, electronic property, and hydrogen adsorption of the alkali auride series, AunM (), , 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 Au5M (, Na, K) and Au3M (, Cs) clusters. In these clusters, the H2 molecule would like to bond with Au atom rather than impurity atom. After adsorption, the AunM structures and H2 molecule in all AunM-H2 clusters are hardly perturbed and still maintain their structural integrity. The geometrical and energetic information indicates a weak adsorption of H2 molecule.
© Società Italiana di Fisica and Springer-Verlag Berlin Heidelberg, 2017