Effect of ion polarization on longitudinal excitations in ionic melts

TL;DR

This paper introduces a simplified polarization model for ionic melts that explains how ion polarization affects optic-like excitations, including frequency softening and increased damping, providing analytical expressions and correlation functions.

Contribution

It presents a new polarization model for ionic melts that captures the effects on collective excitations, extending beyond rigid-ion models.

Findings

Polarization causes softening of optic mode frequencies.

Increased damping of optic modes due to polarization.

Analytical expressions for dipole modes are derived.

Abstract

A simplified model for a collective dynamics in ionic melts is proposed for the description of optic-like excitations. Within a polarization model of ionic melt the analytical expressions for optic and relaxation dipole modes are obtained. The considered model allows one to describe a softening of frequency and an increase of damping of optic modes caused by polarization processes in comparison with the rigid-ion model. The contributions related with ion polarization to time correlation functions are calculated.