X-ray Thomson scattering in warm dense matter

The scattering of photons in plasmas is an important diagnostic tool. Especially, the region of warm dense matter can be probed by X-ray Thomson scattering. The scattering cross-section is related to the dynamic structure factor S(w,omega). We improve the standard treatment of the scattering on free electrons within the random phase approximation (RPA) by including collisions. The dielectric function is calculated in the Born-Mermin approximation. The inclusion of collisions modifies the dynamic structure factor significantly in the warm dense matter regime. We conclude that a theoretical description beyond the RPA is needed to derive reliable results for plasma parameters from X-ray Thomson scattering experiments.