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The controllable preparation of ligand-protected clusters is still an unresolved problem, which may be due to that their formation mechanism is unclear. We propose that the ligand is the key to solve the above problems. Here, by using p -, m -, and o -methylbenzenethiol ligand protected gold clusters as examples, we try to explore the effect of ligand structures on ligand-protected gold clusters. The geometrical structures, relative stabilities and surface properties of small-sized ligand-protected gold clusters [Au-SR] 1-8 (SR = p -/ m -/ o -MBT) have been systematically studied based on the density functional theory. The results show that the ground state structures of [Au-SR] 1-8 clusters tend to form closed rings except for [Au-SR] 1,2 . The different structures of ligand have significant effect on the structures and stabilities of ligand-protected clusters. By analyzing their surface properties and possible growth patterns, it is found that [Au-SR] 1,2 clusters serve as the basic building blocks, and the larger clusters can be regarded as the combinations of them. This study provides some insights into the effect of ligands on ligand-protected clusters, which is useful for understanding the formation mechanism of ligand-protected clusters.

The density functional method with relativistic effective core potential has been employed to investigate systematically the geometrical structures, relative stabilities, growth-pattern behaviors, and electronic properties of small bimetallic M(2)Au(n) (M = Ag, Cu; n = 1-10) and pure gold Au(n) (n ≤ 12) clusters. The optimized geometries reveal that M(2) substituted Au(n+2) clusters and one Au atom capped M(2)Au(n-1) structures are dominant growth patterns of the stable alloyed M(2)Au(n) clusters. The calculated averaged atomic binding energies, fragmentation energies, and the second-order difference of energies as a function of the cluster size exhibit a pronounced even-odd alternation phenomenon. The analytic results exhibit that the planar structure Ag(2)Au(4) and Cu(2)Au(2) isomers are the most stable geometries of Ag(2)Au(n) and Cu(2)Au(n) clusters, respectively. In addition, the HOMO-LUMO gaps, charge transfers, chemical hardnesses and polarizabilities have been analyzed and compared further.

First-principle density functional theory is used for studying the anion gold clusters doped with magnesium atom. By performing geometry optimizations, the equilibrium geometries, relative stabilities, and electronic and magnetic properties of [Au(n)Mg]⁻ (n = 1-8) clusters have been investigated systematically in comparison with pure gold clusters. The results show that doping with a single Mg atom dramatically affects the geometries of the ground-state Au(n+1)⁻ clusters for n = 2-7. Here, the relative stabilities are investigated in terms of the calculated fragmentation energies, second-order difference of energies, and highest occupied−lowest unoccupied molecular orbital energy gaps, manifesting that the ground-state [Au(n)Mg]⁻ and Au(n+1)⁻ clusters with odd-number gold atoms have a higher relative stability. In particular, it should be noted that the [Au₃Mg]⁻ cluster has the most enhanced chemical stability. The natural population analysis reveals that the charges in [Au(n)Mg]⁻ (n = 2-8) clusters transfer from the Mg atom to the Au frames. In addition, the total magnetic moments of [Au(n)Mg]⁻ clusters exhibit an odd-even oscillation as a function of cluster size, and the magnetic effects mainly come from the Au atoms.