Dielectric function and diffusivity of nonideal plasmas

The dielectric function for a two-component (hydrogen) plasma at arbitrary degeneracies is considered in the entire (k, omega)-space. Collisions are t reated in Born approximation leading to a (k, omega)-dependent collision in tegral. Two possible limits are considered: (1) k --> 0 (first), omega --> 0 (second) leading to the dc conductivity sigma. (2) omega --> 0 (first), k --> 0 (second) leading to the diffusivity D. The relation between sigma an d D is discussed.