EXACT EIGENVALUE EQUATION FOR A FINITE AND INFINITE COLLECTION OF MUFFIN-TIN POTENTIALS - COMMENT

In a recent paper, Badralexe and Freeman purport to provide a proof to the effect that the multiple-scattering-theory treatment of waves propagating through a set of potential cells bounded by nonoverlapping spheres, muffin-tin potentials, is valid only in the limit in which the radius of the sphere vanishes (-function potentials). In particular, the authors claim that the well-known Korringa-Kohn-Rostoker method for determining the electronic structure of solids leads to a secular equation which is only approximately valid and cannot give the exact energy levels. It is the purpose of this paper to disprove this claim. © 1990 The American Physical Society.