### Scientific Research and Interests

My work has involved areas of Theoretical Solid State Physics, in particular (1) the general theory of disordered substitutional alloys, the calculation of heats of mixing, of effective interactions and the construction of alloy phase diagrams from first principles, (2) the theory of magnetism of transition-metal alloys, (3) the properties of systems with reduced symmetry, such as surface properties of pure materials and alloys, including the first-principles calculation of composition profiles, (4) the transport properties, e.g. electric conductivity of substitutionally disordered alloys, (5) formal methods in electronic structure and in the application of multiple-scattering theory-Green function techniques to the study of materials properties, and (6) the systematic treatment of correlation effects in solids. I am also interested in the possibility of combining real space methods for electronic structure calculations with molecular dynamics techniques. This might lead to a powerful new approach for studying the electronic structure of not only solid materials but liquids as well. For the last several years I have been involved with the development of formalism within density functional theory. In collaboration with M. Däne, I have succeeded in providing a unique and rigorous treatment of the Coulomb interaction (exchange terms) in implementations of the Kohn-Sham formalism of density functional theory. The method solves the self-interaction problem and is applicable to atoms, molecules, clusters, and extended systems (solids), as well as plasmas.

These studies have also led to a general solution of the so-called v-representability problem through the establishment of a rigorous mathematical procedure that determines whether or not a given density corresponds to the ground state of a many-particle interacting electron system under an external potential, v(r), and if it does, determines the potential.