Investigation of Gd$_{3}$N@C$_{2n}$ (40 $\leq$ $n$ $\leq$ 44) family by Raman and inelastic electron tunneling spectroscopy

The structure and vibrational spectrum of Gd$_{3}$N@C$_{80}$ 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 Gd$_{3}$N$-$C$_{80}$ bond which reduces the ideal icosahedral symmetry of the C$_{80}$ 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 Gd$_{3}$N@C$_{2n}$ (40 $\leq$ $n$ $\leq$ 44) family as well as Y$_{3}$N@C$_{80}$, Lu$_{3}$N@C$_{80}$, and Y$_{3}$N@C$_{88}$ for comparison. Conductance measurements have been performed on Gd$_{3}$N@C$_{80}$ and reveal a Kondo effect similar to that observed in C$_{60}$.