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Endohedral metallofullerenes are novel forms of carbon-based materials, where one or more atoms are encapsulated in the fullerene cage. Due to their unique electronic and magnetic properties, metallofullerenes are promising candidates for applications in nanotechnology and nanoelectronics. Here we present a low temperature scanning tunneling microscopy (LT-STM) study of electronic and vibrational properties of Ce@C82 and Ce2@C80 on Cu(111). Cerium-containing fullerenes were produced by the contact-arc technique. For the separation and purification of the samples two stages High Performance Liquid Chromatography (HPLC) was used. The internal structure of the molecules was clearly resolved in the STM images and the variety of the internal patterns indicates, that the metallofullerenes can bound to the surface in different configurations. Electronic spectra for differently oriented molecules were measured by scanning tunneling spectroscopy (STS). The vibrational properties of the metallofullerenes were analysed using inelastic electron tunneling spectroscopy (IETS). Ab-initio density-functional theory (DFT) calculations indicate that modes resolved by IETS for Ce@C82 are dominated by the vibrations of the C82 cage and contain no significant contribution form the encaged Ce atom. We find that the intensity of the vibrational signal depends on the molecular orientation, which suggests that the adsorption geometry affects the molecular electron-phonon coupling. In case of Ce2@C80, apart from the modes related to the cage, also a low frequency mode was resolved. We discuss the possibility that the low energy mode can be associated with a vibration of the two encaged Ce atoms. |