Mysteries surrounding the carbon equation of state

For the past several years, various groups have performed shock and release measurements on carbon, starting from diamond initial states, which access fairly low-density, high-temperature regimes. Recent equation of state models for carbon constructed from ab initio electronic structure calculations seem to be in notable disagreement with these measurements. We will briefly review the current situation, after which we will discuss a few ways in which we have tried to better understand this conundrum.

This work was performed under the auspices of the U.S. Department of Energy by Lawrence Livermore National Laboratory under Contract DE-AC52-07NA27344