  The structure and vibrational spectrum of Gd3N@C80 is studied through Raman
and inelastic electron tunneling spectroscopy (IETS) as well as density
functional theory (DFT) and universal force field (UFF) calculations. Hindered
rotations, shown by both theory and experiment, indicate the formation of a
Gd3N-C80 bond which reduces the ideal icosahedral symmetry of the C80 cage. The
vibrational modes involving the movement of the encapsulated species are a
fingerprint of the interaction between the fullerene cage and the core complex.
We present Raman data for the Gd3N@C2n (40 < n < 44) family as well as Y3N@C80,
Lu3N@C80, and Y3N@C88 for comparison. Conductance measurements have been
performed on Gd3N@C80 and reveal a Kondo effect similar to that observed in
C60.
