Electronic and geometric properties of exohedral potassium-fullerenes

We investigate the structural and electronic properties of KnC60 (n ⩽ 12) clusters in the framework of density-functional theory. The behavior of the potassium atoms over the C60 surface is analyzed. For K12C60, potassium atoms are found to form 4-atom islands on the surface. The charge transfer and the energetics are discussed in relation with available results.