Ln@C60 endohedral fullerenes: A DFT analysis for the complete series from lanthanum to lutetium

Abstract

We report on a computational study of the complete series of lanthanide atoms encapsulated in C60 fullerene molecule (Ln@C60) by using density functional theory with the PBE functional complemented with the Grimme’s dispersion correction (PBE-D). The goal of the present survey is to account for the influence of step-by-step adding 4f-electrons in lanthanides on the geometrical and electronic properties of Ln@C60 endohedral species. In order to compare the results obtained, we tested two double-numerical basis sets: DN and DND, which are equivalent to the 6-31G and 6-31G(d) Pople-type basis sets. The electronic parameters analyzed comprised the HOMO, LUMO and HOMO-LUMO gap energies, as well as the charge and spin of the encapsulated metal atom. The La and Lu atoms exhibit no tangible spin contribution, whereas in the remaining Ln@C60 species unpaired electrons are found on both lanthanide atom and C60 cage. An intermediate case is the Yb@C60 complex, where only a minor presence of unpaired electrons on the central metal was found.