and throughout this work we use the PW92 parametrization for xc and assume zero polarization. In the right panel of Figure , we show the resulting σλ=1 . We can see that as r s → 0, σλ=1 → σx , since w λ=1 reduces to x . As r s increases, correlation between electrons becomes stronger and σλ=1 increases. The range of σ values for the UEG is in line with the previous 'exact' σλ=1 plots for atoms and H 2 , where negative σ was observed for the exchange regimes, and was around 0 for weak correlations. When correlation becomes very strong, σλ=1 approaches 1/2 (e.g, stretched H 2 ). For the UEG, when r s ≥ 19.3, w λ→∞ (r) even exceeds 1/2 and slowly tends to ∼ 0.8 as r s → ∞.