Carbon at pressures in the range 0.1-1 TPa (10 Mbar)

Single-shock (Hugoniot) equation-of-state data of shock-compressed C (graphite) are reported at pressures of 480 and 760 GPa (7.6 Mbar). Graphite is shock-compressed completely into a diamond-like phase at pressures below 80 GPa. At pressures of 80-800 GPa comparison of an ensemble of experimental Hugoniot data for shock-compressed graphite and diamond, and theoretical calculations of the Hugoniots of graphite and diamond, and the 0 K isotherm of diamond suggest diamond melts at similar to 300 GPa on the Hugoniot of graphite and that the diamond phase is the ground-state structure of C up to at least 600 GPa. (C) 2001 American Institute of Physics.