A new evidence of first-order phase transition for hydrogen at 3000 K

Abstract

The molecular-dynamics simulations based on density functional theory have been explored to study the properties of warm dense hydrogen in the density range and temperature between 1000 and 3000 K. We find clear evidence of pressure discontinuity at the isotherm of 3000 K by large-scale simulations, which also confirm the first-order nature of this transition. It indicates that the molecular liquid phase is unexpectedly stable, and the temperature of transition towards an atomic liquid phase is much higher than previously predicted. A new transition line has been located in the phase diagram.