  Solid state high resolution $^{13}C$ NMR has been used to investigate the
physical properties of pristine $C_{60}$ after intercalation with molecular
oxygen. By studying the dipolar and hyperfine interactions between Curie type
paramagnetic oxygen molecules and $^{13}C$ nuclei we have shown that neither
chemical bonding nor charge transfer results from the intercalation. The $O_2$
molecules diffuse inside the solid $C_{60}$ and occupy the octahedral sites of
the fcc crystal lattice. The presence of oxygen does not affect the fast
thermal reorientation of the nearest $C_{60}$ molecules. Using Magic Angle
Spinning we were able to separate the dipolar and hyperfine contributions to
$^{13}C$ NMR spectra, corresponding to buckyballs adjacent to various numbers
of oxygen molecules.
