Umbrella-shaped vs planar; evolutionary search for BnQ, Be©BnQ (n=6-12, Q=0,-1) clusters

We used the universal structure predictor: evolutionary xtallography (USPEX) method conjugated with density functional theory (DFT) calculations to investigate the global search of the neutral and anionic B-n(Q) and Be (c) B-n(Q) (n = 6-12, Q = 0,-1) clusters. The lowest-energy structures of B-n(Q), Be (c) B-n(Q) clusters mainly featured planar or quasi-planar for all clusters, except for Be (c) B-7(0/-) and Be (c) B-8(0/-) (umbrella-shaped) clusters. Based on obtained data, it can be seen that the most stable structure of neutral and anionic clusters are the same except for B-6(0)/(-) and Be (c) B-11(0/-) clusters. Based on our calculations, the Be (c) B-8 cluster with umbrella-shaped (heptagonal bipyramidal) can be observed as a magic cluster, which is extremely thermodynamic and kinetic stability. A net charge transfer from the Be metal atom to the boron motif demonstrated that the electrostatic interactions has an essential role in the stability of boron-doped clusters. Furthermore, molecular orbital (MO) and adaptive natural density partitioning (AdNDP) analyses ascertained that the enhanced stability of Be (c) B-8 resulted from strong interactions between the 2 s orbital of Be atom and the 2s2p orbitals of the B atoms. Moreover, the B-B sigma bonds in the B-8 shell, which can be considered sigma-anti-aromaticity and pi-aromaticity, contribute to the stabilization of the Be (c) B-8 cluster. (C) 2021 Elsevier B.V. All rights reserved.

Automated summary

This study utilized the USPEX method combined with DFT calculations to investigate B-n(Q) and Be(c) B-n(Q) clusters. The majority of clusters exhibited planar or quasi-planar structures, while the Be(c) B-8 cluster was umbrella-shaped. The Be(c) B-8 cluster was identified as a magic cluster due to its exceptional thermodynamic and kinetic stability.