TIGHT-BINDING APPROACH TO THE ELECTRONIC-PROPERTIES OF IONIC AND COVALENT LIQUIDS

The paper discusses two tight-binding models to describe the interactions in compound-forming liquid alloys A//cB//1// minus //c; A is less electronegative than B. Such tight-binding models are especially useful to discuss trends in a series of comparable alloys. The Coherent Potential Approximation (CPA) model including electron-phonon coupling describes well the resistivity and other electronic properties of systems with a compound-forming composition satisfying the usual valence rules; i. e. based on charge transfer. The second model uses a Modified Bethe lattice to describe the atomic structure. It applies to covalently bonded clusters of like atoms in the condensed phase. Stability of clustering with respect to no clustering is discussed.