Empirical tight-binding parameters for solid C₆₀

We present a tight-binding model for the electronic structure of solid C₆₀ using four (one 2s and three 2p) orbitals per carbon atom. The model has been developed by fitting the tight-binding parameters to the ab initio pseudopotential calculation of Troullier and Martins (1992) in the face-centred cubic (Fm3) phase. Following this, calculations of the energy bands and the density of electronic states have been carried out as a function of the lattice constant. Good agreement has been obtained with the observed lattice-constant dependence of T_c using McMillan's formula. Furthermore, calculations of the electronic structure are presented in the simple cubic (Pa3) phase.