Electronic structure of Eu@C60 studied by XANES and UV-VIS absorption spectra

Eu endohedral C-60, Eu@C-60, has been extracted with aniline from soot prepared by are-heating of a graphite/Eu2O3 composite rod and obtained at high concentration by combining sublimation and repeated high-performance liquid chromatography. The laser desorption time-of-flight mass spectrum showed a pronounced peak of Eu@C-60(+). The W-VIS absorption spectrum of this sample has a red-shift in the onset (> 900 nm) in comparison with those for C-60 and C-70, as expected from electron transfer from the Eu atom to the C-60 cage. The valence state of the Eu atom in Eu@C-60 has been determined to be +2 by Eu L-m-edge XANES. (C) 2000 Elsevier Science B.V. All rights reserved.