Mn@Si14+: a singlet fullerene-like endohedrally doped silicon cluster

Abstract

The electronic structure of Mn@Si₁₄⁺ is determined using DFT and CASPT2/CASSCF(14,15) computations with large basis sets. The endohedrally Mn-doped Si cationic cluster has a D_3h fullerene-like structure featuring a closed-shell singlet ground state with a singlet–triplet gap of ∼1 eV. A strong stabilizing interaction occurs between the 3d(Mn) and the 2D-shell(Si₁₄) orbitals, and a large amount of charge is transferred from the Si₁₄ cage to the Mn dopant. The 3d(Mn) orbitals are filled by encapsulation, and the magnetic moment of Mn is completely quenched. Full occupation of [2S, 2P, 2D] shell orbitals by 18 delocalized electrons confers the doped Mn@Si₁₄⁺ cluster a spherically aromatic character.