Entropy of melting: Its effect on the liquid-liquid phase change of carbon

Graphite melting experiments reported recently suggest that the enthalpy of melting of graphite decreases slowly and linearly with pressure, unlike our previous suggestion, which included a liquid-liquid phase change like those observed in other systems. We have investigated the possibility that this smooth pressure dependence could eliminate the liquid-liquid phase change. Our analysis shows that the available experimental enthalpies of melting cannot rule out such a phase change. An accurate determination of the (P,T) melting line curvature can shed light on the presence or absence of such a phase change.