A THEORETICAL APPROACH TO C-82 AND LAC82

In view of the recent experimental interest, the relative stabilities of the C82 isomers and the electronic properties of LaC82 are investigated by means of molecular orbital calculations. It is calculated that the most stable C82 isomer has C2 Symmetry, as detected most abundantly via NMR measurement. An interesting finding is that the electronic structure of LaC82 depends strongly on the position of the La atom. At the energetically most favorable position the electronic state is described as La3+C823-, as suggested from the EPR measurement. It is predicted that the La atom is trapped inside the cage of C2 symmetry and is strongly bound to the cage carbons; LaC82 has strong electron-donating character.