B. Kessler et al., EVIDENCE FOR INCOMPLETE CHARGE-TRANSFER AND LA-DERIVED STATES IN THE VALENCE BANDS OF ENDOHEDRALLY DOPED LA-AT-C-82, Physical review letters, 79(12), 1997, pp. 2289-2292
Photoelectron spectra from sublimed layers of chromatographically sepa
rated La@C-82 are presented. Using photon energies corresponding to th
e La 3d to 4f transition, a resonant enhancement of the La-derived val
ence states is observed. From the calculated resonant intensities of L
a 5d and 5p states in a La atom we estimate that about 1/3 of an elect
ron charge is left in the La-valence orbitals for La@C-82. In contrast
to previous interpretations of La core-level photoemission studies ou
r results demonstrate that the La valence electrons are not completely
delocalized on the fullerene cage.