Understanding the geometric structure, electronic and stability properties of anionic germanium-doped magnesium clusters: Gas-phase GeMgn− (n = 2–12) DFT study

Abstract

Gas-phase GeMgn− (n = 2–12) clusters were fully researched through CALYPSO and Gaussian software with DFT in this work. Structural evolution studies show that all GeMgn− (n = 3–12) clusters grow based on tetrahedron-like and tent-like geometries. It is found that GeMg8− cluster possesses the highest relative stability and can be regarded as a “magic” cluster. The charge transfer property is illustrated by calculations showing that Ge atoms always passively accept electrons, while Mgn hosts always lose electrons. The valence electron configuration confirms that the cluster formation is mainly originated from the interaction of the 4s4p-orbitals hybridization of Ge with the 3s3p-orbitals hybridization of Mg atoms. The simulated PES of the ground state of GeMgn− (n = 2–12) clusters were also reported. ELF analysis indicates that Mg-Mg covalent bonding occurs in clusters larger than GeMg4− and Ge-Mg bonding is affected by Mg-Mg bonding into the low ELF region. DOS analysis was implemented for the GeMg8− cluster and it can be found that the Ge and Mg atoms contribute to the orbitals mainly from the σ-bonds. Finally, to provide data support for finding GeMg8− cluster in spectroscopic experiments, theoretical calculations of IR and Raman spectra of GeMg8− were performed.