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.
Categories: cond-mat