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In this paper, we used CALYPSO program which is conjuncted with DFT to investigate Li doped small-sized neutral Bn clusters. From ground-state and low energy structures, the properties and geometric significance of Li-doped boron clusters are greatly affected. Except for LiB9, which adds a B atom on preceding LiB8 boron wheel, the ground-state clusters of LiBn are formed by replacing the terminal boron atom of the Bn+1 clusters in the same size with a Li atom or by adding a Li atom to the Bn clusters. The transition point from 2 to 3D configuration of LiBn clusters appears at n = 5. The stability of LiBn clusters was analyzed by calculating the average binding energy, Gibbs free energy, first-order differential energy, second-order differential energy, HOMO–LUMO gap (the energy gap between the highest occupied and lowest unoccupied molecular orbital) and charge transfer. The results show that the LiB11 cluster with excellent symmetry and planar structure is the relative most stable structure. Molecular orbital and chemical bonding analysis indicated that the main reason for the stability of the LiB11 cluster is mainly due to the strong s-p bonding of B–B. [ABSTRACT FROM AUTHOR]

In this work, particle swarm optimization (CALYPSO) is combined with density functional theory (DFT) to perform a comprehensive structure search for the Bn0/−Rb2 (n = 1–12) clusters. The ground-state structures of the Bn0/−Rb2 (n = 1–12) clusters were determined based on the total energy of the obtained structures. It was also found that when the number of B atoms was low, the doped cluster geometry mainly behaved as planar or planar-like. The addition of doped Rb atoms distorts the boron clusters, with the doping position around the main body of boron. The stability analysis shows that the B8Rb2 cluster with a double pyramidal structure and a symmetry of D7h has excellent stability in the studied system. The energy gap between the highest occupied molecular orbital and the lowest unoccupied molecular orbital is 6.14 eV. Bonding analysis is performed using molecular orbitals and density of states, and the results show that strong communications between the two Rb atoms and the B-atom bulk dominate their significant stability, where mainly the p atom orbital of the Rb atoms interacts with the s and p atom orbitals of the B atoms. Furthermore, the bond level density and naturally adapted orbital analysis revealed that the formation of effective π-type naturally adapted orbitals between the doped Rb atoms and the B atoms, with a higher delocalization index, is one of the reasons for the higher cluster stability. [ABSTRACT FROM AUTHOR]

Projects about magnesium-based doped of transition metal have constantly attracted much attention in cluster science, while the research of Co, Fe, Ni doped Mid-Sized Mg16 clusters has not been reported. Here, the geometric construction and electronic properties of neutral and negative Mg16X (X = Co, Fe, Ni) clusters were researched by unbiased CALYPSO structure search codes and subsequent DFT calculations at the B3PW91 level. The results show that Fe and Co atoms are more likely to replace the central bits of the caged Mg170/− cluster, but the excellent and stable configuration of the Mg170/− cluster is perfectly maintained. Simultaneously, the doping of Co and Fe can cause the cluster to produce the corresponding magnetic moment. The caged Mg16Co− clusters with a central Co atom have good binding energy, local charge transfer and HOMO–LUMO gap according to stability analysis, which indicates that Mg16Co− clusters has better relative stability. In addition, it is found that there is an intense interaction between Mg-3s, p and Co-3d AO (molecular orbitals) through the analysis of molecular orbitals and adaptive natural density partitioning (AdNDP), which may be the main reason for the high stability of Mg16Co− clusters. [ABSTRACT FROM AUTHOR]

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]

[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]