title: Density functional calculations of 3He chemical shift in endohedral helium fullerenes: Neutral, anionic, and di-helium species.
abstract: We report density functional calculations of 3He nuclear magnetic resonance chemical shifts in a series of experimentally known endohedral helium fullerenes, He(n)@Cm(q) (n = 1, 2; m = 60, 70, 76, 78; q = 0, 6-), including for the first time anionic and di-helium species. Despite the lack of dispersion in the density functional model, the results are in promising agreement with experiment. Density functional theory performs better than Hartree-Fock for the anionic systems. In the di-helium species confined in the small C60 cage, besides the atomic displacements from the center position, the direct He-He interactions contribute to the 3He shift.
authors.affiliation: Laboratory of Physical Chemistry, Department of Chemistry, University of Helsinki, PO Box 55 (A. I. Virtasen aukio 1), FIN-00014, Helsinki, Finland. michal.straka@helsinki.fi
authors.forename: Michal
authors.initials: M
authors.lastname: Straka
authors.forename: Juha
authors.initials: J
authors.lastname: Vaara