Diatomic melting curves to very high pressure

Abstract
Using new high-temperature diamond-anvil-cell designs, together with a variety of optical techniques, we have measured the melting curves of N2 to 18.0 GPa, O2 to 16.3 GPa, and F2 2.5 GPa. One triple point is found on the N2 curve and two on the O2 curve. A simple ‘‘effective rotation’’ model of librational motions in the solid is used to obtain good theoretical fits to the experimental curves.