Properties of carbon up to 10 million kelvin from Kohn-Sham density functional theory molecular dynamics

TL;DR

This study uses Kohn-Sham density functional theory molecular dynamics to accurately model the properties of dense carbon plasmas at extreme temperatures up to 10 million Kelvin, providing detailed equations of state and transport properties.

Contribution

It presents the first comprehensive Kohn-Sham DFT MD calculations of dense carbon properties at high temperatures, validated against other methods and databases, without empirical approximations.

Findings

EOS and Hugoniot agree with PIMC and SESAME data

Calculated ion-ion structure factor and viscosity at high T

Validated Kohn-Sham DFT MD for extreme plasma conditions

Abstract

Accurately modeling dense plasmas over wide ranging conditions of pressure and temperature is a grand challenge critically important to our understanding of stellar and planetary physics as well as inertial confinement fusion. In this work, we employ Kohn-Sham density functional theory (DFT) molecular dynamics (MD) to compute the properties of carbon at warm and hot dense matter conditions in the vicinity of the principal Hugoniot. In particular, we calculate the equation of state (EOS), Hugoniot, pair distribution functions, and diffusion coefficients for carbon at densities spanning 8 g/cm$^3$ to 16 g/cm$^3$ and temperatures ranging from 100 kK to 10 MK using the Spectral Quadrature (SQ) method. We find that the computed EOS and Hugoniot are in good agreement with path integral Monte Carlo results and the SESAME database. Additionally, we calculate the ion-ion structure factor and viscosity for selected points. All results presented are at the level of full Kohn-Sham DFT MD, free of empirical parameters, average-atom, and orbital-free approximations employed previously at such conditions.