Theoretical Study on Structural Properties and Infrared Spectra of M@B₁₂N₁₂ (M=La-Lu) Clusters

The geometric structures, electronic properties, electric dipole characteristics, and infrared absorption spectra of M@B₁₂N₁₂ (M=La-Lu) clusters were invested detailed by Density functional theory. The results show that after embedding lanthanide atoms into B₁₂N₁₂ clusters, the structural stability is enhanced, and the molar volume exhibits a gradually decreasing trend with the increase of atomic number. In terms of spin multiplicity, it is a singlet state after embedding Sm, Er and Yb atoms; a doublet state when doped with Pr, Pm, Ho, Tm and Lu; a triplet state when doped with Ce, Gd and Dy; a quartet state when embedding La, Eu and Tb; and a quintet state when doped with Nd. The HOMO-LUMO energy gap decreases, and the chemical activity is improved. The HOMO orbitals tend to be distributed near M atoms and N atoms, while most of the LUMO orbitals are still distributed around B atoms. After doping, the electric dipole moment of the clusters shows a variation trend of first increasing and then decreasing, and the electric dipole moment of some structures is close to zero. The polarizability exhibits oscillating characteristics, among which the value of B₁₂N₁₂Tm cluster is the largest. With the increase of atomic number, the number of absorption peaks in the infrared spectrum increases. Among them, the infrared absorption peaks of M@B₁₂N₁₂ (M=Nd, Sm, Er) clusters undergo a blue shift, while the rest show a red shift.