Molecules ionization at phase transition in warm dense hydrogen
A new idea is developed that the fluid–fluid phase transition in warm dense hydrogen is related to the partial ionization of molecular hydrogen H2 with formation of molecular ions H2+ and H3+ . Conventional ab initio quantum modeling is applied. Proton pair correlation functions (PCF) obtained are used for the nonconventional diagnostics of the phase transition and elucidation of its nature for temperatures 700-1500 K. Short- and longrange changes of PCF’s are studied. H2 molecules ionization and molecular ions H2+ and H3+ appearance is revealed. The validity of the soft sphere model is tested for the long-range order.