Reduced Ionic Diffusion by the Dynamic Electron-Ion Collisions in Warm Dense Hydrogen

TL;DR

This paper investigates how dynamic electron-ion collisions influence ionic diffusion in warm dense hydrogen, revealing significant reductions in diffusion and proposing a validated correction model for these effects across various conditions.

Contribution

It introduces a new model incorporating collision-induced friction effects into ionic diffusion calculations, validated by multiple simulation methods.

Findings

Ionic diffusion is significantly reduced by dynamic electron-ion collisions.

The CIF model accurately predicts diffusion across a wide range of densities and temperatures.

Modified EOCP model effectively incorporates collision effects for better diffusion estimates.

Abstract

The dynamic electron-ion collisions play an important rolein determining the static and transport properties of warmdense matter (WDM). Electron force field (eFF) method is applied to study the ionic transport properties of warm densehydrogen. Compared with the results from quantum moleculardynamics and orbital-free molecular dynamics, the ionicdiffusions are largely reduced by involving the dynamic collisions of electrons and ions. This physics is verified by quantum Langevin molecular dynamics (QLMD) simulations, which includes electron-ion collisions induced friction(EI-CIF) into the dynamic equation of ions. Based on these new results, we proposed a model including the correctionof collisions induced friction of the ionic diffusion. The CIF model has been verified to be valid at a wide range ofdensity and temperature. We also compare the results with the Yukawa one component plasma (YOCP) model andEffective OCP (EOCP) model. We proposed to calculate the self-diffusion coefficients using the EOCP model modifiedby the CIF model to introduce the dynamic electron-ion collisions effect.