Fig. 7: PIMC based estimation of the effective ionization degree Z* following the approach introduced by Böhme et al.43.
From: Unraveling electronic correlations in warm dense quantum plasmas
a Fourier component of the density ρq [see main text] as a function of the perturbation amplitude A for four different wave vectors q [error bars show the 1σ Monte Carlo uncertainty]. The dashed black lines show cubic fits [Eq. (9)], and the dotted red lines the corresponding linear-response limit. b Linear density response function χ(q) for NBe = 4 (green) and NBe = 10 (red) beryllium atoms [error bars show the fit uncertainty in the linear coefficients]. Dashed blue: density response of a uniform electron gas (UEG) at the same conditions, corresponding to a fully ionized system; solid red: density response of a UEG assuming a fraction of free electrons of 3.6/4. The vertical dotted yellow line indicates the Fermi wavenumber qF = (9π/4)1/3/rs. The red mesh indicates the wavenumber region of interest in which the density response is sensitive to electronic localization around the ions.
