Endohedral boron-doped scandium clusters BmScn−m+/0 (m = 2–3, n = 3–13): triangular – linear rearrangement of the B3 dopant

Abstract

A theoretical investigation, employing density functional theory with the PBE functional and the Def2-TZVP basis set, comprehensively explores the geometric and electronic structures and properties of the boron doped scandium clusters B_mSc_n−m^+/0 with m = 2–3 and n = 3–13. Introduction of B atoms significantly enhances the stability of the resulting clusters with respect to the initial counterparts. As the number of B atoms increases, the stability of the doped clusters improves, following the order: B₃Sc_n−3^+/0 > B₂Sc_n−2^+/0 > BSc_n−1^+/0 > Sc_n^+/0. Notably, the B₂@Sc₈ cluster represents the smallest fully endohedral doubly doped cage, and the B₃@Sc₁₀ is the smallest fully endohedral triply doped cage reported to date. The size with 8 Sc atoms plays a crucial role in the structural evolution of both doubly doped B₂Sc_n−2^+/0 and triply doped B₃Sc_n−3^+/0 series. For the doubly doped species, this size marks an exohedral-to-endohedral transition, while in the triply doped species, it marks an interconversion of the B₃ dopant from a triangular to a linear arrangement. In the triangular B₃ trimer, the electron and charge distribution are evenly shared among the three B atoms, whereas in the linear B₃ trimer, these distributions are unequal. Additionally, the geometric and electronic structures of the linear-B₃ doped B₃@Sc₈ can serve as basic building blocks for the construction of larger clusters.