  In non-ideal plasmas, the dielectric function has to be treated beyond the
random phase approximation. Correlations and well as collisions have to be
included. These corrections are known as (dynamical) local field corrections.
With the help of the Zubarev approach to linear response theory, a relaxation
time approximation is proposed leading to an interpolation scheme between
static local field corrections and the Drude model in the long wave length
limit. The approach generalizes the Mermin approximation for the dielectric
function and allows for the inclusion of a dynamical collision frequency.
Exploratory calculations for a classical two-component plasma at intermediate
coupling are presented.
