Generalized dielectric permittivity of ice

The generalized dielectric permittivity describes the electric response of both bound charges (normal dielectric constant) and free charges (conductivity). The generalized dielectric permittivity of ice (water) has been calculated within the model of classical quasiparticles as a function of the wave vector and frequency $\epsilon(\mathbf{q},\omega)$. At zero wave vector and nonzero frequency, this function describes the response to a uniform alternating electric field, whereas at nonzero wave vector and zero frequency, it describes the screening of a static electric field. At simultaneously nonzero wave vector and frequency, it can be used to study electromagnetic waves in ice. In addition, the generalized dielectric permittivity allows the calculation of the dynamic correlation function of the electric polarization in terms of the fluctuation-dissipation theorem.