On the fundamental equations of the Korringa-Kohn-Rostoker (KKR) version of the coherent potential approximation (CPA)

It is shown that the fundamental equation normally solved in a KKR-CPA calculation leads to an effective lattice which satisfies the CPA condition more generally than has been noted before. This fact allows the authors to study the partially averaged charge density beyond the unit cell surrounding the selected site and fluctuations about the CPA.