The structure in warm dense carbon

The structure of the fluid carbon phase in the pressure region of the graphite, diamond, and BC8 solid phases is investigated. We find increasing coordination numbers with an increase in density. From zero to 30 GPa, the liquid shows a decrease of packing efficiency with increasing temperature. However, for higher pressures, the coordination number increases with increasing temperature. Up to 1.5 eV and independent of the pressure up to 1500 GPa, a double-peak structure in the ion structure factors exists, indicating persisting covalent bonds. Over the whole pressure range from zero to 3000 GPa, the fluid structure and properties are strongly determined by such covalent bonds.