Theoretical investigations on the structure-property relationships of Au13 and AuxM13-x nanoclusters

As a fundamental building block in ultrasmall, noble metal nanoclusters, icosahedral AuxM13-x structures have recently attracted extensive research interest. In this study, density functional theory (DFT) and time-dependant DFT calculations have been carried out to investigate the structure-property (optical and electronic) relationships of a series of Au-13 and AuxM13-x (M = Au, Ag, Cu, and Pd) nanoclusters co-protected by phosphine and chloride ligands. It was found that the size of the peripheral ligands significantly affects the geometric structure: the larger exterior ligands (with a larger cone angle) result in relatively longer Au-M bond distances and weaker metallic interactions within the AuxM13-x core. Therefore, the optical peak (in the UV-vis spectrum) corresponding to the HOMO -> LUMO transition red-shifts accordingly. When different foreign atom(s) are incorporated, the preferential doping site is different, and the electronic and optical structures alter accordingly.