First-principles multiphase equation of state of carbon under extreme conditions

Multicomponent-Multiphase Equation of State for Carbon

The PANDA code is used to build a tabular equation of state (EOS) table for carbon. The model includes three solid phases (graphite, diamond, and metallic) and a fluid phase mixture containing three molecular components (C1, C2, and C3). Separate EOS tables were first constructed for each solid phase and for each molecular species in the fluid phase. Next, a mixture/chemical equilibrium model w...

Carbon under extreme conditions: phase boundaries and electronic properties from first-principles theory.

At high pressure and temperature, the phase diagram of elemental carbon is poorly known. We present predictions of diamond and BC8 melting lines and their phase boundary in the solid phase, as obtained from first-principles calculations. Maxima are found in both melting lines, with a triple point located at approximately 850 GPa and approximately 7,400 K. Our results show that hot, compressed d...

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 densitytemperature space, 1.5 − 13.9 g cm and 10 − 10 K. In the molecular dissociation regime, we extend the pressure-temperatu...

Crystallography Under Extreme Conditions: State of the Art and Perspectives

An improved equation of state under solar interior conditions

This paper presents a simple and efficient equation of state which can be used for quick and accurate computing of the thermodynamic functions of partly ionized and weakly coupled plasmas. Based on the free energy minimization method, the improvement of the equation of state includes a detailed account of the physical processes of non-ideal effects consisting of electron degeneracy, Coulomb cou...