Structural Evolution of Small-Sized Phosphorus-Doped Boron Clusters: A Half-Sandwich-Structured PB Cluster.

The present study is a theoretical investigation into the structural evolution, electronic properties, and photoelectron spectra of phosphorus-doped boron clusters PB (n = 3-17). The results of this study revealed that the lowest energy structures of PB (n = 3-17) clusters, except for PB, exhibit planar or quasi-planar structures. The lowest energy structures of PB (n = 3-17), with the exceptions of PB, PB, and PB, are planar or quasi-planar. The ground state of PB has an umbrella-shaped structure, with C symmetry. Interestingly, the neutral cluster PB has a half-sandwich-like structure, in which the P atom is attached to three B atoms at one end of the sandwich, exhibiting excellent relative and chemical stability due to its higher second-order energy difference and larger HOMO-LUMO energy gap of 4.31 eV. Subsequently, adaptive natural density partitioning (AdNDP) and electron localization function (ELF) analyses demonstrate the bonding characteristics of PB and PB, providing support for the validity of their stability. The calculated photoelectron spectra show distinct characteristic peaks of PB (n = 3-17) clusters, thus providing theoretical evidence for the future identification of doped boron clusters. In summary, our work has significant implications for understanding the structural evolution of doped boron clusters PB (n = 3-17), motivating further experiments regarding doped boron clusters.