Looking inside an endohedral fullerene: Inter- and intramolecular ordering of Dy3N@C80 (Ih) on Cu(111)

The inter- and intramolecular ordering of the trimetallic nitride endohedral fullerene Dy3N@C-80 with icosahedral cage symmetry I-h on Cu(111) has been studied by scanning tunneling microscopy and synchrotron-based x-ray photoelectron diffraction (XPD). Dy3N@C-80 (I-h) is found to form ordered islands consisting of domains of equally oriented molecules. As for C-60 on the same substrate, the cage is facing with a hexagon toward the surface, which is however slightly tilted for C-80. The endohedral nitrogen atom remains at a position close to the geometrical center of the cage. Resonant XPD on the M-V edge shows that the encaged Dy3N unit takes well-defined orientations with respect to the C-80 cage and the Cu(111) substrate.