Structural, electronic, and optical properties of the Ag–Cu clusters with the equal number atoms

The structural, electronic, and optical properties of the Ag n Cu n ( n = 7–14) clusters with the equal number of the Ag and Cu atoms are systematically investigated by using the density functional theory method. The results indicate that as n is 9, the structures of the Ag n Cu n clusters begin to form the icosahedral core, and most Ag–Cu clusters with icosahedral cores have high stability. The Ag 8 Cu 8 cluster has the highest mixing degree. The Ag 10 Cu 10 cluster has relatively high energetic and electronic stability. For the density of states at the Fermi level, the Ag 7 Cu 7 , Ag 8 Cu 8 , Ag 9 Cu 9 , Ag 10 Cu 10 , and Ag 14 Cu 14 clusters are mainly contributed by Cu atoms, while the Ag 11 Cu 11 , Ag 12 Cu 12 , and Ag 13 Cu 13 clusters are mainly contributed by Ag atoms. Interestingly, the Cu 16 -II cluster is magnetic. The absorption spectra of the Ag n Cu n clusters are red-shift comparing with the pure Ag 2 n clusters, but they are blue-shift comparing with the pure Cu 2 n clusters. The absorption properties of the Ag n Cu n clusters in the visible region are better than the pure clusters. Graphical abstract