First-Principles Equation of State Calculations of Warm Dense Nitrogen

Using path integral Monte Carlo (PIMC) and density functional molecular dynamics (DFT-MD) simulation methods, we compute a coherent equation of state (EOS) of nitrogen that spans the liquid, warm dense matter (WDM), and plasma regimes. Simulations cover a wide range of density-temperature space, \(1...

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Bibliographic Details
Published in:arXiv.org 2016-01
Main Authors: Driver, K P, Militzer, B
Format: Article
Language:English
Subjects:
Computer simulation
Correlation analysis
Equations of state
First principles
Hugoniot curves
Ionization
Molecular dynamics
Monte Carlo simulation
Phase diagrams
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Summary:Using path integral Monte Carlo (PIMC) and density functional molecular dynamics (DFT-MD) simulation methods, we compute a coherent equation of state (EOS) of nitrogen that spans the liquid, warm dense matter (WDM), and plasma regimes. Simulations cover a wide range of density-temperature space, \(1.5-13.9\)~g\(~\)cm\(^{-3}\) and \(10^3-10^9\)~K. In the molecular dissociation regime, we extend the pressure-temperature phase diagram beyond previous studies, providing dissociation and Hugoniot curves in good agreement with experiments and previous DFT-MD work. Analysis of pair-correlation functions and the electronic density of states in the WDM regime reveals an evolving plasma structure and ionization process that is driven by temperature and pressure. Our Hugoniot curves display a sharp change in slope in the dissociation regime and feature two compression maxima as the K and L shells are ionized in the WDM regime, which have some significant differences from the predictions of plasma models.
ISSN:2331-8422
DOI:10.48550/arxiv.1601.05787