Contributions to the self-energy of a wave propagating in a disordered array

We study the self-energy of a scalar wave propagating in a disordered static array of spherical scatterers. We employ the cluster expansion developed in a preceding article and provide detailed expressions for many contributions to the self-energy. The two-body term is covered completely. The three-body term is treated only in part, but we believe that those contributions which are important at not too high density are accounted for. Through resummation some of the contributions to the self-energy involve a large number of scatterers.