# Dynamical structure factor of strongly coupled ions in a dense quantum plasma

## TL;DR

This study investigates how electronic correlations influence the dynamical structure factor of strongly coupled ions in dense quantum plasmas, revealing their significant impact on ionic modes and the applicability of simplified models.

## Contribution

It introduces a detailed molecular dynamics approach incorporating electronic correlations via the Singwi-Tosi-Land-Sj"olander approximation, enhancing understanding of ionic DSF in dense plasmas.

## Key findings

- Electronic correlations lower ion-acoustic mode frequencies.
- Correlations extend the hydrodynamic description's wave-number range.
- Even weak electronic coupling affects ionic sound speed.

## Abstract

The dynamical structure factor (DSF) of strongly coupled ions in dense plasmas with partially and strongly degenerate electrons is investigated. The main focus is on the impact of electronic correlations (non-ideality) on the ionic DSF. The latter is computed by carrying out molecular dynamics (MD) simulations with a screened ion-ion interaction potential. The electronic screening is taken into account by invoking the Singwi-Tosi-Land-Sj\"olander approximation, and compared to the MD simulation data obtained considering the electronic screening in the random phase approximation and using the Yukawa potential. %This allows us to gain insight into the impact of the electronic non-ideality on the ionic DSF. We find that electronic correlations lead to lower values of the ion-acoustic mode frequencies and to an extension of the applicability limit with respect to the wave-number of a hydrodynamic description. Moreover, we show that even in the limit of weak electronic coupling, electronic correlations have a non-negligible impact on the ionic longitudinal sound speed. Additionally, the applicability of the Yukawa potential with an adjustable screening parameter is discussed, which will be of interest, e.g., for the interpretation of experimental results for the ionic DSF of dense plasmas.