Ionisation Calculations using Classical Molecular Dynamics

Fuente: arXiv
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Main Authors: Plummer, Daniel, Svensson, Pontus, Gericke, Dirk O., Hollebon, Patrick, Vinko, Sam M., Gregori, Gianluca
Format: Preprint
Published: 2024
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author Plummer, Daniel
Svensson, Pontus
Gericke, Dirk O.
Hollebon, Patrick
Vinko, Sam M.
Gregori, Gianluca
author_facet Plummer, Daniel
Svensson, Pontus
Gericke, Dirk O.
Hollebon, Patrick
Vinko, Sam M.
Gregori, Gianluca
contents By performing an ensemble of molecular dynamics simulations, the model-dependent ionisation state is computed for strongly interacting systems self-consistently. This is accomplished through a free energy minimisation framework based on the technique of thermodynamic integration. To illustrate the method, two simple models applicable to partially ionised hydrogen plasma are presented in which pair potentials are employed between ions and neutral particles. Within the models, electrons are either bound in the hydrogen ground state or distributed in a uniform charge-neutralising background. Particular attention is given to the transition between atomic gas and ionised plasma, where the effect of neutral interactions is explored beyond commonly used models in the chemical picture. Furthermore, pressure ionisation is observed when short range repulsion effects are included between neutrals. The developed technique is general, and we discuss the applicability to a variety of molecular dynamics models for partially ionised warm dense matter.
format Preprint
id arxiv_https___arxiv_org_abs_2409_01078
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Ionisation Calculations using Classical Molecular Dynamics
Plummer, Daniel
Svensson, Pontus
Gericke, Dirk O.
Hollebon, Patrick
Vinko, Sam M.
Gregori, Gianluca
Plasma Physics
By performing an ensemble of molecular dynamics simulations, the model-dependent ionisation state is computed for strongly interacting systems self-consistently. This is accomplished through a free energy minimisation framework based on the technique of thermodynamic integration. To illustrate the method, two simple models applicable to partially ionised hydrogen plasma are presented in which pair potentials are employed between ions and neutral particles. Within the models, electrons are either bound in the hydrogen ground state or distributed in a uniform charge-neutralising background. Particular attention is given to the transition between atomic gas and ionised plasma, where the effect of neutral interactions is explored beyond commonly used models in the chemical picture. Furthermore, pressure ionisation is observed when short range repulsion effects are included between neutrals. The developed technique is general, and we discuss the applicability to a variety of molecular dynamics models for partially ionised warm dense matter.
title Ionisation Calculations using Classical Molecular Dynamics
topic Plasma Physics
url https://arxiv.org/abs/2409.01078