XAFS study on metal endohedral fullerenes

Structure of metal endohedral fullerenes is studied by XAFS and XANES. The Sc-Sc distance of 2.23(1) Angstrom determined from Sc K-edge XAFS supports the formation of a triangular Sc-3 cluster in Sc-3@C-82 as is found by MEM analysis for the X-ray diffraction. Gd L-III-edge XAFS of Gd@C-82 shows tha t the first and the second neigboring Gd-C distances are 2.51(2) and 2.85(4 ) Angstrom, respectively. The La-La distance of La-2@C-80 has been determin ed to be 3.90(1) Angstrom at 40 K. This value does not change when increasi ng temperature [3.90(2) Angstrom at 240 K]. The position and the valenece o f the Eu atom in Eu@C-60 are also discussed based on Eu L-III-edge XAFS and XANES.