Vibrational spectrum of the endohedral Y₂C₂@C ₉₂ fullerene by Raman spectroscopy: Evidence for tunneling of the diatomic C₂ molecule

The structure and vibrational spectrum of the novel endohedral fullerene Y₂C₂@C₉₂ was studied by Raman spectroscopy, with particular emphasis on the rotational transitions of the diatomic C ₂ unit in the low-energy Raman spectrum. We report evidence for tunneling of this unit through the C₂ rotation plane and observe anomalous narrowing in a hindered rotational mode. We also report complementary density functional theory calculations that support our conclusions and discuss potential applications to quantum computing and nonvolatile memory devices.