Endohedral dimetallofullerenes Sc-2@C-84 and La-2@C-80. Are the metal atoms still inside the fullerene cages?

In order to provide insight into the motion of metal atoms in endohedral dimetallofullerenes, Sc-2@C-84 and La-2@C-80 are investigated as typical examples by use of ab initio molecular orbital and nonlocal density functional methods. It is suggested that the two Sc atoms can oscillate with considerable amplitude while the two La atoms can circulate inside the fullerene cage with small barriers of approximate to 5 kcal/mol. It is expected that such metal motions will lead to interesting electronic and magnetic properties.