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

Single-shock (Hugoniot) equation-of-state data of shock-compressed C (graph ite) are reported at pressures of 480 and 760 GPa (7.6 Mbar). Graphite is s hock-compressed completely into a diamond-like phase at pressures below 80 GPa. At pressures of 80-800 GPa comparison of an ensemble of experimental H ugoniot data for shock-compressed graphite and diamond, and theoretical cal culations 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 gra phite and that the diamond phase is the ground-state structure of C up to a t least 600 GPa. (C) 2001 American Institute of Physics.