MONOMETALLOFULLERENE TM-AT-C-82 - PROOF OF AN ENCAPSULATED DIVALENT TM ION BY HIGH-ENERGY SPECTROSCOPY

The valency of the Tm ion in the endohedral monometallofullerene Tm@C- 82 with C-3v symmetry has been studied using high-energy spectroscopy. The resemblance of the Tm 4d core level photoemission spectrum to tha t calculated for Yb3+ suggests a 4f(13) ground state configuration for the encapsulated Tm ion. This could be proven beyond doubt by measure ments of the characteristic 4f multiplet structure in photoemission. F urthermore, the Tm 4d excitation spectrum measured using volume sensit ive electron energy-loss measurements in transmission confirms that th is material is indeed the first monometallofullerene containing a diva lent lanthanide ion.