Semi-Empirical Model For Permittivity Of Warm Dense Matter

The permittivity of Lorentz plasmas and wide-range expression for effective frequency of collisions of electrons are considered in wide temperature range. The proposed expression fulfills all limiting cases (high-and low-frequency skin effect, degenerate and non-degenerate plasmas) and permits one to incorporate different physical phenomena in warm dense matter like contribution of electron-phonon collisions and umklamp process to permittivity. For the case of aluminum plasmas, the model takes into account both intraband and interband contributions to permittivity via semi-empirical Huttner model modified in such a way to ensure proper description of optical properties of aluminum at room temperatures.