DFT Analysis of the Electronic and Structural Properties of Lanthanide Nitride Cluster Fullerenes Ln3N@C80

Abstract

We have undertaken a DFT study of the nitride cluster fullerenes (NCFs) Ln3N@C80 for the complete series of fourteen lanthanides plus lanthanum by using the PBE functional with the Grimme’s dispersion correction (PBE-D2). We tested the DN and DND basis sets, which are equivalent to 6-31G and 6-31G(d) Pople-type basis sets, respectively. Due to the known convergence problems when treating lanthanide-containing systems, only with the DN basis set was it possible to complete the calculations (geometry optimization and analysis of selected electronic parameters) for all the fifteen NCFs. We found that the bending of the Ln3N cluster increases as the ionic radius increases, in general agreement with the available X-ray diffraction data. The Ln3N cluster becomes more planar as the Ln–N bond length is contracted, and the C80 cavity slightly deforms. The HOMO-LUMO energies and distribution, as well as the charge and spin of the encapsulated metal ions, are analyzed.