The Anomalous Compressibility and Metallization of Deuterium under   Shock-Wave Compression
  High values of deuterium compressibility under shock-wave compression, recently discovered in several experiments, are explained by an unusual dielectric-metal phase transition from a dense molecular gas into a liquid-metal atomic gas. This phase transition recently described by authors was named the dissociative phase transition (DPT). The same phase transition describes a significant scattering of experimentally measured densities within an area of anomalous compressibility. 
A.L. Khomkin and A.S. Shumikhin
physics.plasm-ph physics.chem-ph