Optical and electronic properties of Cu doped Ag clusters

The optical and electronic characteristics of Ag13, Ag12Cu and Cu13 clusters with Ih symmetry were investigated using density functional theory (DFT) methods. Absorption peak red shifts clearly with increasing the Cu atoms in comparison of the absorption spectra of [Ag13]+, [Ag12Cu]+ and [Cu13]+ clusters at the singlet state. The electronic state densities show that the d-electrons play a crucial role in the Ag12Cu cluster. Mulliken charge analysis reveals the electrons of outer shell silver atoms in Ag12Cu cluster are more active than these of Ag13 and Cu13 clusters when excited from ground state to singlet state. HOMO–LUMO gaps of three clusters show the Ag12Cu cluster has a better metallic nature. The values of ionization potential (IP) and electronic affinity (EA) indicate that the Ag12Cu cluster has a more electronic activity than that of Ag13 or Cu13 cluster, which is interested to understand a catalytic mechanism of bimetallic nanoalloys.

► Our results reveal the optical and electronic characteristics of Ag13, Ag12Cu and Cu13 clusters.
► The adsorption spectrum of Cu doped Ag13 cluster of presents a red shift.
► The Cu doping causes d-electrons transferred in Ag12Cu cluster.
► The Ag12Cu clusters have a more active electronic characteristic.
► Our calculations are important for revealing the optical and catalytic mechanisms of alloyed AgCu nanoparticles.