Theoretical study of geometry and electronic properties of medium-sized doped clusters KBn (n = 2 − 12)

In this study, we employed the CALYPSO software in conjunction with DFT calculations to investigate KB_n (n = 2 − 12) clusters and determine their ground state structures. Through structural and stability analyses, we elucidated the structural evolution patterns of KB_n (n = 2 − 12) clusters; notably, we identified two clusters, KB₇ and KB₉, which exhibit similar structures characterized by planar molecular wheel configurations of the boron framework, albeit with differences in stability. Additionally, charge transfer analysis of each ground state structure revealed that the position of the doped K atom significantly influences the bonding characteristics within the cluster. Further examination of the bonding characteristics of the KB₇ and KB₉ clusters showed substantial contributions from the B-2s, B-2p, K-4s, and K-5s orbitals. In both KB₇ and KB₉ clusters, there is a strong interaction between K and B atoms, leading to the formation of robust K–B and B–B covalent bonds. Ultimately, the interaction region indicator method indicates that, in the KB₇ and KB₉ clusters, there are not only chemical bonds between B atoms, but also significant weak interactions.