Investigating the structural and electronic properties of anionic calcium-doped magnesium clusters

Abstract

In recent years, the structure and properties of alkaline earth metal-doped Mg clusters have attracted much attention. Here, we investigated the structural properties, stability analysis, chemical bonding properties and charge transfer properties of Ca2Mgnˉ (n=1-15) nanoclusters by using the efficient CALYPSO structure search software and the DFT full domain search method based on B3PW91 level calculation. It is found that most of their ground state structures can inherit pure Mgn+2ˉ (n=1-15) clusters with high symmetry. We further compare the experimental and theoretical PES spectral data using pure Mgn+2ˉ (n=1-15) and find a high agreement, which also indicating the validity of my calculated all-domain most stable structure. We found the outstanding stability of the pentagonal Ca2Mg7ˉ by stability analysis. Charge transfer occurred in all Ca2Mgnˉ clusters, and this transfer was from Ca to Mg. The chemical bonding properties and molecular orbital revealed that the contribution of Mg-s and Mg-p to the molecular orbitals led to the formation of strong Mg-Mg bonds in the Ca2Mg7ˉ cluster, the s-p hybridization between Ca and Mg atoms and between Mg and Mg atoms also led to more powerful Mg-Mg bonds and Ca-Mg bonds, which is strong evidence for the stability of the Ca2Mg7ˉ clusters.