Longitudinal optic excitations in ionic melts within an ion-polarization model: A theoretical study

In the present paper we used ion-polarization model to study collective excitations in ionic melts. Based on the extended model for collective dynamics in ionic melts (which takes into account fluctuations of charge density, charge current, and its time derivative) we obtained the set of collective excitations in the system, containing relaxation mode related to electric conductivity, two propagating optic-like modes and relaxation mode due to polarization processes. The received analytical expressions for the collective modes take into account corrections caused by ion polarizability comparing to rigid-ion model. The obtained results correctly describe a reduction of frequency of optic-like modes and an increase of damping due to polarization processes. The results are consistent with other theoretical works and results of computer simulations.