Structure and electronic properties of Dy@C82 studied by UV-VIS absorption, X-ray powder diffraction and XAFS

Two isomers of Dy@C(82) were separated by high performance liquid chromatography (HPLC). and their UV-VIS absorption spectra were measured to characterize these isomers. The crystalline powder of Dy@C(82) was obtained by removing the solvent (toluene) at 250 degreesC under vacuum. The X-ray diffraction pattern can be indexed with fcc crystal lattice, as that in La@C(82). The lattice constant a at 298 K, 15.86(1) Angstrom, is dose to that of La@C(82), 15.78 Angstrom. The distances between Dy and the first and second nearest C atoms are determined to be 2.52(2) and 2.86(2) Angstrom, respectively. on the basis of Dy L(III)-edge EXAFS. The XANES shows that the valence of the Dy atom in Dy@C(82) is +3. (C) 2001 Elsevier Science B.V. All rights reserved.