Quantum-mechanical calculation of ionization potential lowering in dense plasmas

TL;DR

This paper introduces a rigorous, parameter-free Hartree-Fock-Slater model for calculating ionization potential depression in dense plasmas, resolving discrepancies in previous models and aligning well with recent experimental data.

Contribution

The authors develop a two-step Hartree-Fock-Slater model that accurately predicts ionization potential depression, improving upon existing models and validated against recent experimental results.

Findings

Model accurately describes experimental Al data.

Standard IPD models are validated and improved.

Addresses discrepancies in previous theoretical predictions.

Abstract

The charged environment within a dense plasma leads to the phenomenon of ionization potential depression (IPD) for ions embedded in the plasma. Accurate predictions of the IPD effect are of crucial importance for modeling atomic processes occurring within dense plasmas. Several theoretical models have been developed to describe the IPD effect, with frequently discrepant predictions. Only recently, first experiments on IPD in Al plasma have been performed with an x-ray free-electron laser (XFEL), where their results were found to be in disagreement with the widely-used IPD model by Stewart and Pyatt. Another experiment on Al, at the Orion laser, showed disagreement with the model by Ecker and Kr\"oll. This controversy shows a strong need for a rigorous and consistent theoretical approach to calculate the IPD effect. Here we propose such an approach: a two-step Hartree-Fock-Slater model. With this parameter-free model we can accurately and efficiently describe the experimental Al data and validate the accuracy of standard IPD models. Our model can be a useful tool for calculating atomic properties within dense plasmas with wide-ranging applications to studies on warm dense matter, shock experiments, planetary science, inertial confinement fusion and studies of non-equilibrium plasmas created with XFELs.