Ab initio calculations of effective cluster interactions which make up the ordering energy of a substitutional alloy are reported. Tendencies toward ordering or phase separation and more generally phase stability in PdV and PdRh substitutional alloys are discussed. The study is based on an extension of the generalized perturbation method to systems describable by muffin-tin Hamiltonians in the framework of the multiple-scattering formalism in conjunction with the Korringa-Kohn-Rostoker coherent potential approximation. Future applications of the method are discussed.

• Received 1 December 1987

DOI:https://doi.org/10.1103/PhysRevB.37.5982