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Bimetallic clusters have received extensive attention due to the changes in their properties and structures. Therefore, the structure and electronic configuration of medium-size Sr-doped magnesium clusters were studied in this work. The CALYPSO (crystal structure analysis by particle swarm optimization) algorithm and DFT (density functional theory) were applied to search, correct energy, and optimize geometry for stable low-energy structures. We described the structural evolution and characteristics of SrmMgn0/− (m = 1,2; n = 10–15) clusters, and found that a few ground-state isomers can maintain the same structure framework as the corresponding pure magnesium clusters. Through relative stability analysis, the SrMg13− cluster with a pyramid shape and Sr2Mg11 cluster with a pagoda-like shape were determined to be the most stable structures. Further analysis of the molecular orbitals and bonding characteristics of SrMg13− and Sr2Mg11 clusters also revealed a strong interaction between Sr and Mg atoms and the s–p bonding of Mg–Mg, which may be the main reason for the high stability of these clusters. We hope that this study will provide guidance for future doping of pure magnesium clusters. [ABSTRACT FROM AUTHOR]

• The evolution of the structures for Mg 2 Bn0/– (n = 1–12) clusters has be elucidated. • The corresponding ground state structures are determined. • The local stable ground state structure is found. • The properties of electrons and bonds of the most stable isomers are discussed. In this paper, a global search for the lowest energy structure of Mg 2 B n 0/- (n = 1–12) clusters is performed based on Density functional theory combined with the particle swarm optimization algorithm program CALYPSO. The geometry, stability, charge transfer, and bonding properties of the clusters were analyzed at the B3LYP/def2-tzvp level. Then Mg 2 B 8 with high symmetry D 4h was found to be the magic numbers cluster among them. The doped clusters Mg 2 B n 0/− were compared with the pure boron clusters B n+2 0/− (n = 1–12) at the same level. The following results are obtained: as the number of boron atoms increases, the boron clusters doped with Mg atoms change from a two-dimensional planar or quasi-plane structure to a three-dimensional structure. The doped magnesium atoms are always positively charged in the convex capped position. And the doping of Mg atoms drives the overall stabilization of the boron clusters and makes the clusters more compact. There is a large amount of charge transfer between the Mg atom and the B atom, and the main orbitals involved are the S and p orbitals. There are strong interactions between the two atoms of boron and magnesium. Through the analysis of the bonding properties, it was found that the s-p hybridization mode between Mg B is the main reason for the enhanced cluster stability. [Display omitted] [ABSTRACT FROM AUTHOR]

• The evolution of the structures for Ca 2 Mg n – (n=1-15) clusters has be elucidated. • The corresponding ground state structures are determined. • One of the most stable structural units are found. • The properties of electrons and bonds of the most stable isomers are discussed. 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 Ca 2 Mg n ˉ (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 Mg n+2 ˉ (n=1-15) clusters with high symmetry. We further compare the experimental and theoretical PES spectral data using pure Mg n+2 ˉ (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 Ca 2 Mg 7 ˉ by stability analysis. Charge transfer occurred in all Ca 2 Mg n ˉ 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 Ca 2 Mg 7 ˉ 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 Ca 2 Mg 7 ˉ clusters. [ABSTRACT FROM AUTHOR]

• The evolution of the structures for Ba n Mg m 0/– (n = 1,2; m = 10–15) clusters has be elucidated. • The corresponding ground state structures are determined. • Two local stable ground state structures are found. • The properties of electrons and bonds of the most stable isomers are discussed. Projects about alkaline-earth metals doped magnesium are hot issues constantly in cluster science, while research in terms of Mid-Sized Ba atoms doped magnesium cluster was unreported. We adopted the CALYPSO method coupled with DFT calculation to simplify the process of structure searching at the range of Ba n Mg m 0/– (n = 1,2; m = 10–15) cluster. We found the doped Ba atoms tend to occupy convex capped sites in each structure. Meanwhile, the six-atom triangular prism as a major structure constructed the great mass of isomers. Based on the result of the relative stability survey, we selected BaMg 13 – and Ba 2 Mg 13 – to conduct further investigations, according to a different numbers of doped Ba atoms. Analysis of the bonding character manifests that the Mg- p orbital takes up the highest proportion for both BaMg 13 – and Ba 2 Mg 13 – cluster at HOMO, LUMO position as well as the existence of strong covalent bonds between Mg-Mg atoms and Ba-Mg atoms. [Display omitted] [ABSTRACT FROM AUTHOR]

[Display omitted] • The evolution of the structures for Ba 2 Mg n (n = 1–10) clusters has be elucidated. • The corresponding ground state structures are determined. • A pagoda-like most-stable structure are found. • The properties of electrons and bonds of the most stable isomers are discussed. This paper reports systematic studies of small sized magnesium clusters doped with two barium atoms in both neutral and anionic species. The search, geometric optimization, and energy correction of stable and low-energy structures were completed using CALYPSO software package and DFT calculations. The structural evolution of Ba 2 Mg n 0/– clusters (n = 1–10) with increasing size were elucidated, and we found that most of the ground-state isomers of them inherit that of the corresponding pure Mg clusters well in terms of structure. After verifying the NBO (natural bond orbital) charge of the low-lying Ba 2 Mg n 0/– clusters (n = 1–10), a new fact was exposed: that all the doped Ba atoms in the structures are positively charged except in Ba 2 Mg–. A pagoda-like most-stable cluster Ba 2 Mg 8 with a HOMO-LUMO gap of 1.59 eV was found by relative stability analysis within the scope of our study. Further analyses of the molecular orbitals and bonding of Ba 2 Mg 8 clusters also revealed a strong interaction between Ba-6 s and Mg-3 p AOs, which may be the main reason for the high stability of Ba 2 Mg 8. We hope our studies will provide guidance for the synthesis and application of doped Mg-based nanomaterials in the future. [ABSTRACT FROM AUTHOR]

[Display omitted] • The evolution of the structures for Sr 2 Mg n (n =1–12) clusters has be elucidated. • The corresponding ground state structures are determined. • Several stable structural units are found. • The properties of electrons and bonds of the most stable isomers are discussed. Alkali earth metal clusters have been the subject of intense interest due to the wide range of applications and unique characteristics of transition from nonmetallic to metallic bond. In this work, the structural evolution and electronic properties of neutral and anionic strontium-doped magnesium clusters have been studied by structural search code of CALYPSO and subsequent calculation of DFT at B3PW91 level. The results reveled that most of the Sr 2 Mg n 0/– clusters are viewed as the substituted structures of corresponding pure magnesium clusters, in which the Sr atoms prefer to occupy the convex capped sites. Analysis of the natural population show that the Sr atoms always play the role of electron donor in the charge transfer process except for Sr 2 Mg 1-3 –. In the range of studied size, the neutral Sr 2 Mg 8 cluster with a tower-like structure and outstanding stability is uncovered. The molecular orbital and chemical bonding analysis indicate that the stronger Sr-Mg interaction lead to s-p hybridization between Sr and Mg atoms can stabilize the Sr 2 Mg 8 cluster. [ABSTRACT FROM AUTHOR]