First principle study on the interactions of Au(Ag₂S)_n (n = 1–8) with Hg⁰ and Hg²⁺

First principle study on the interactions of Au(Ag₂S)_n with Hg⁰ and Hg²⁺ have been carried out. Au(Ag₂S)_n clusters can absorb Hg⁰ and Hg²⁺. As n increases, the structure of Au(Ag₂S)_n clusters changes from open to cage structure. For Au(Ag₂S)_nHg and Au(Ag₂S)_nHg²⁺ clusters, the structures can hardly keep cage structure. Stability analysis reveals that Au(Ag₂S)_n (n = 7), Au(Ag₂S)_nHg (n = 5, 8) and Au(Ag₂S)_nHg²⁺ (n = 1, 4, 8) clusters are more stable than other size clusters. Hg⁰ is mainly physically adsorbed on Au(Ag₂S)_n clusters, while Hg²⁺ can chemically absorbed on Au(Ag₂S)_n clusters for n = 1–8. According to the projected density of states (PDOS) properties, the energies of s, p and d orbitals shift before and after bonding. According to electron localization function (ELF) and non-covalent interactions (NCI) analysis, non-covalent interactions present in Au(Ag₂S)₈Hg and Au(Ag₂S)₈Hg²⁺ clusters, what’s more, it can play a role in stabilizing the clusters. From the thermodynamic point of view, the formation reactions of Au(Ag₂S)_nHg²⁺ are spontaneous, while the formation reactions of Au(Ag₂S)_nHg are nonspontaneous. After the formation reaction of Au(Ag₂S)_nHg, the charges of Hg increase, while those of Hg²⁺ decrease.