Rapid 3D 'Roll-Up' of Gas-Phase Small-Sized Planar Gold Clusters and Relative Affinity and Alienation for Mg and Ge: A DFT Study of Mggeaun (N=1-12) Clusters

Abstract

The geometric structure, stability, charge transfer and chemical bond properties of Mg- and Ge-doped Au_n(n=1-12) clusters were comprehensively studied by CALYPSO cluster structure search software together with DFT. It is found that the geometries of the MgGeAu_n (n=2-12) clusters rapidly 'roll-up' into 3D structures, and the ground state isomer structure of MgGeAu₃ is used as 'seed' to grow. Even-sized ground state MgGeAu_n(n is even) isomers are more stable than odd-sized ones, and MgGeAu₄ and MgGeAu 6 are proved to have higher stability than other clusters. Charge transfers and electron configuration studies indicate that Mg atoms are electron donors, while Ge and most Au atoms are electron acceptors, and Mg and Ge atoms are 3s3p orbitals and 4s4p orbitals hybridized, while Au is 5d6s6p orbitals hybridized. Most importantly, the chemical bond analysis based on AIM theory was carried out on the ground state isomers of each cluster, focusing on the number of chemical bonds, the size of the cluster in which a certain type of chemical bond occurs, the type of chemical bond, and the composition of molecular orbitals. The results show that the relative affinity of gold clusters to Mg atom and the relative alienation from Ge cause Mg to 'immerse' inside the clusters, while Ge is 'squeezed out' at the edge.