Fig. 4: Ionization degree of warm dense Be at T ~ 155 eV as a function of the mass density ρ.

Red area: present PIMC results [with corresponding uncertainty range], see the Methods section for details; black crosses: DFT-MD taken from ref. ¹¹; dotted green: Steward-Pyatt; dashed blue: OPAL; purple bar: DFT-MD analysis of the Rayleigh weight³¹ (see Appendix D of ref. ³¹ for computational details). Using our new PIMC capabilities to interpret the NIF data at 120° (red circle) substantially changes the inferred parameters compared to the chemical model used in the original ref. ¹¹ (dataset #3).