Investigation of Gd ₃N@C _2n (40≤n≤44) family by Raman and inelastic electron tunneling spectroscopy

The structure and vibrational spectrum of Gd ₃N@C ₈₀ is studied through Raman and inelastic electron tunneling spectroscopy as well as density-functional theory and universal force field calculations. Hindered rotations, shown by both theory and experiment, indicate the formation of a Gd ₃N-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 ₃N@C _2n (40≤n≤44) family as well as Y ₃N@C ₈₀, Lu ₃N@C ₈₀, and Y ₃N@C ₈₀ for comparison. Conductance measurements have been performed on Gd ₃N@C ₈₀ and reveal a Kondo effect similar to that observed in C60.