Consideration of the Electronic Structure of Endohedral Fullerenes from a View Point of the Fullerene Cage Size and Cage Structure

We have been measuring the photoelectron spectra of endohedral fullerenes and clarified the transfer of electrons from the entrapped species to the cage as well as the amounts of transferred electrons. Now we have an accumulation of ultraviolet photoelectron spectroscopic data of endohedral fullerenes, which enables us to consider the effects of the cage size and cage geometry to their electronic structure systematically. I am going to present our recently obtained photoelectron spectra of various sized endohedral fullerenes encapsulating two lutetium atoms, a cluster of two lutetium and carbon atoms and a Sc₃N cluster, and discuss the cage size effect to the electron transfer from the entrapped species to the cage and geometry of the entrapped species. Ultraviolet photoelectron spectra of I_h- and C_2v-C₈₀ caged endohedral fullerenes will also be given and their electronic structure difference will be discussed with an aid of DFT calculation.