Shock compressing diamond to a conducting fluid

Laser generated shock reflectance data show that diamond undergoes a continuous transition from optically absorbing to reflecting between Hugoniot pressures 600<1000 GPa. The data are consistent with diamond having a thermal population of carriers at P(H)similar to600 GPa, undergoing band overlap metallization at P(H)similar to1000 GPa and melting at 800<1000 GPa. The results agree well with an equation of state model that predicts that elemental carbon remains solid throughout the interior of Neptune.