Structure and stability of Mo-doped Cu (n=1-12) clusters: DFT calculations

The thermodynamic and chemical stability of CunMo (n=1-12) clusters are evaluated by density functional theory (DFT) calculations. The most stable structures are obtained by using the SCG (systematic growth algorithm) and corroborated by simulated annealing. The lowest-energy structures of CunMo clusters are planar and quasiplanar for n=3-7, while icosahedral-like structures for n=8-12. The relative stability of the clusters is further analyzed through the average binding energy, the fragmentation energy and second-order energy differences. The results of EB shows that doping with Mo slightly reduces the stability of small clusters with n=1-7, however, for n=8 onward, the doped clusters become more stable due to the formation of the icosahedral structure at Cu12Mo. The results show that Cu4Mo, Cu7Mo, Cu9Mo and Cu12Mo, are more stable than the neighbor clusters. In addition, the doped clusters show higher HOMO-LUMO gaps and total spin magnetic moments compared to pure Cun clusters. The IR spectra of the clusters are provided.