First-principles equation of state calculations of warm dense nitrogen

Article

关键词: COMPRESSED LIQUID-NITROGEN;    X-RAY-DIFFRACTION;    FLUID NITROGEN;    HIGH-PRESSURE;    MOLECULAR DISSOCIATION;    SHOCK COMPRESSION;    PHASE-TRANSITION;    SOLID NITROGEN;    HIGH-DENSITIES;    GPA;   

DOI  :  10.1103/PhysRevB.93.064101

来源: SCIE

【 摘 要 】

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 gcm(-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.

【 授权许可】

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