Mn2@Si15: the smallest triple ring tubular silicon cluster

Abstract

The smallest triple ring tubular silicon cluster Mn₂@Si₁₅ is reported for the first time. Theoretical structural identification shows that the Mn₂@Si₁₅ tubular structure whose triple ring is composed by three five-membered Si rings in anti-prism motif, is stable in high symmetry (D_5h) and singlet ground state (¹A₁′). The dimer Mn₂ is placed inside the tubular along the C₅ axis, and the Mn dopant form single Si–Mn bonds with Si skeleton, whereas the Mn–Mn is characterized as a triple bond. The effect of Mn₂ on the stability of the Si₁₅ triple ring structure arises from strong orbital overlap of Mn₂ with Si₁₅.