Metal-cage hybridization in endohedral La@C60, Y@C60 and Sc@C60

Stimulated by the recent resonant photoelectron spectroscopy studies on La@C82 which found a nonzero charge density localized on the La atom, local density functional calculations have been performed on La@C60, Y@C60 and Sc@C60. In contrast to previous charge-transfer model, strong hybridization between the La(Y, Sc) d-valence orbitals and the cage orbitals occurs in our calculations. After hybridization the unpaired electron is primarily delocalized on the cage and the occupied orbitals have significant d character. The effective electron charge left on the metal valence orbitals is about 1.