Effective-medium approximation for liquid metals

An effective-medium theory is developed for the electronic structure of liquid metals. The medium is characterized by a medium site-site scattering matrix and a medium intersite propagator. These are self-consistently determined by removing an ion from the medium and then examining the scattering from that ion. To third order in the $T$-matrix expansion, the result corresponds to evaluating the three-particle distribution function in the superposition approximation, and this is more accurate than previous work. The result reduces to the coherent-potential approximation for the case of binary alloys. A tight-binding-model version of the theory is also discussed.