This award is being made through the NSF initiative for Computational Approaches to Real Materials which was part of the High Performance Computing and Communications Initiative. This award was rated High Priority by panel review. Research on the electronic structure and properties of substitutional alloys will be conducted in collaboration with Oak Ridge National Laboratory using the 2048-node Intel PARAGON computer. Recent developments of theory and methodology have progressed to where calculations of formation energies and other physical properties of solid substitutional alloys give results that are in good agreement with experiment. The proposed research will extend this theory and develop new algorithms to elucidate the underlying electronic mechanisms in several problems of technological interest, such as the origins of site selectivity of third alloy additions in binary intermetallic alloys. Since the required calculations are presently beyond the limits of current vector supercomputers, the theory will be implemented on the new generation of massively parallel supercomputers, and the associated algorithms and codes will be developed. %%% This computational research will focus on calculating the electronic properties of important classes of metallic alloys. The calculations are sophisticated ones which are accurate in comparison with actual measurements. Due to the complexity of this work, the calculations will be performed on a new generation massively parallel computer at Oak Ridge National Laboratory. The necessary computer codes will be developed. This research is funded through a NSF initiative called Computational Approaches to Real Materials which is part of the High Performance Computing and Communication Initiative.