Solubility of carbon in high-pressure and high-temperature water

The solubility of carbon in water at the pressure of 7.7 GPa and at temperatures of 1000-2900 K is investigated by means of statistical mechanical theory, and it is found that the excess saturation concentration of carbon in hot water is very sensitive to the temperature. The peak of excess saturation concentration is located at 2450 K, according to calculations using the code CHEQ, where the driving force for graphite-to-diamond transformation reaches the maximum. The conclusions are consistent with those from recent diamond synthesis experiments.