We could see in Fig. that the GEO weights of PBE and PBE0 are substantially different. To shed more light on that and gain insight into the position of the α minimum for α-PBE in Figure , we consider here how the α-PBE GEO components vary for the formaldehyde molecule. This molecule is chosen as its optimal α value is about the same as that for the whole B2se dataset (about 0.2 at the AVTZ basis set). The results are shown in Figure . From the top panel, where AVTZ is used, we first note that the GEO curve is accurately described by that of GEO s . Furthermore, the angle contribution to GEO is very small, and thus the GEO black curve is essentially the sum of its single-bonds and double-bond components (the light blue and blue curves). Up to α ∼ 0.15, most of GEO comes from the single bonds, whereas in the region for α values in between ∼ 0.35 and ∼ 0.6, it mostly comes from the double bond. The minimum of the GEO curve (black) is at about α = 0.2, and is closer to the minimum of the double-bond component (α ∼ 0.09) than to that of the single-bonds component (α ∼ 0.45), as the latter minimum is shallower. The large distance between the blue and light blue minima do not allow α-PBE to be very accurate for both single-and double-bond of formaldehyde at the same time. Thus, at the α ∼ 0.2 minimum there is some contribution from both bond types. In the bottom panel of Figure , we repeat the same plot, but within AVDZ. The situation in this panel is similar to that of the upper panel, with the difference that the position of the minima of the four curves are now shifted towards larger α values (only the angle between the bonds is most accurate at α = 1 for both basis sets). This observation is in-line with the earlier analysis that focused on the changes in the total GEO values as one goes from AVTZ to AVDZ.