At what pressure does solid hydrogen become a metal

At $T < 100\,\mathrm{K}$, determine the pressure at which solid hydrogen becomes metallic and whether the transition goes from insulating molecular phase III to a metallic molecular phase or to atomic hydrogen. An answer combines infrared reflectivity showing a Drude response, dc electrical transport, and structure determination above $\sim 4\,\mathrm{Mbar}$.

Reproducible dc transport with metallic temperature dependence plus diffraction or Raman identification of the phase, at a stated calibrated pressure.