The electronic structure of arbitrarily shaped atomic clusters

In this paper a formal MSW approach is established to calculate the energy levels of atomic clusters and molecules. It is shown that the standard secular equation is formally preserved, though the muffin-tin approximation is replaced by the only assumption that the total potential is a sum of (possibly overlapping) atomic contributions. The transition matrix still contains all information about the scattering properties of the atoms, but is no longer diagonal in the angular momentum indices.