Global minimum Pt₁₃M₂₀ (M = Ag, Au, Cu, Pd) dodecahedral core-shell clusters

In this work, we report finding dodecahedral core-shell structures as the putative global minima of Pt₁₃M₂₀ (M = Ag, Au, Cu, Pd) clusters by using the basin hopping method and the many-body Gupta model potential to model interatomic interactions. These nanoparticles consist of an icosahedral 13-atom platinum core encapsulated by a 20 metal-atom shell exhibiting a dodecahedral geometry (and I_h symmetry). The interaction between the icosahedral platinum core and the dodecahedral shell is analyzed in terms of the increase in volume of the icosahedral core, and the strength and stickiness of M-Pt and M-M interactions. Low-lying metastable isomers are also obtained. Local relaxations at the DFT level are performed to verify the energetic ordering and stability of the structures predicted by the Gupta potential finding that dodecahedral core-shell structures are indeed the putative global minima for Pt₁₃Ag₂₀ and Pt ₁₃Pd₂₀, whereas decahedral structures are obtained as the minimum energy configurations for Pt₁₃Au₂₀ and Pt ₁₃Cu₂₀ clusters.