On the static dielectric function of liquid metals

A formalism is presented for the calculation of the dynamic dielectric function, epsilon(k,w), of simple liquid metals. This is based on the assumptions that the liquid metal may be regarded as an isotropic and homogeneous binary mixture of classical rigid ions and conduction electrons which interact weakly with one another. The formalism is applied to study the static dielectric function, epsilon(k,0), of the liquid alkali and alkaline-earth metals near their melting points. Specifically, the calculations make use of the Neutral Pseudo Atom pseudopotential, the Local Density Approximation dielectric function and the Variational Modified Hypernetted Chain theory of liquids. The whole theory is free of adjustable parameters and uses as input data the thermodynamic state of the system (ionic number density and temperature), the valence, and the atomic number. The obtained results show that the behaviour of the dielectric function of the simple liquid metals, near their melting points, is dominated by the ionic contributions.