Strong metal-cage hybridization in endohedral La@C82, Y@C82 and Sc@C82

Stimulated by the recent resonant photoelectron spectroscopy studies on La@C82 who found a nonzero charge density localized on the La atom, local density functional calculations have been performed on La@C82, Y@C82 and Sc@C82. In contrast to previous charge transfer model for La@C82, Y@C82 and d-electron localization model for Sc@C82, strong hybridization between the La (Y, Sc) d valence orbitals and the cage orbitals have been found in our calculations. Through hybridization the unpaired electron is primarily delocalized on the cage but the occupied valence orbitals contain significant d character.