(Top raw) Snapshots of silicon during thermal melting into low-density liquid phase at different time instants after the FEL pulse irradiation corresponding to the absorbed dose of 0.72 eV/atom, photon energy of 30 eV, and FWHM pulse duration of 60 fs. (Bottom raw) Powder diffraction patterns for the corresponding atomic structures obtained with X-ray photons of wavelength of 1.54 Å.