CHARGE-DISTRIBUTION IN K3C60 REVISITED - INCOMPLETE ALKALI-TO-C-60 ELECTRON-TRANSFER

The charge distribution in K3C60 has been calculated in the theoretical framework of a crystal orbital formalism based on an INDO (intermediate neglect of differential overlap) Hamiltonian. We predict a non-integral potassium-to-C60 charge transfer (CT) with a clear discrimination between tetrahedral (t) and octahedral (o) alkali atoms. The CT from the o sites exceeds the CT from the t positions. The influence of the incomplete alkali ionization on the binding energy of core electrons is discussed. It is demonstrated that the present theoretical results provide a straightforward explanation of photoemission experiments on K3C60.