, suggesting less long-range dispersion in the former. The dispersion corrections do not afford (nor did we expect) quantitative agreement with genuine dispersion energies, represented here by SAPT+MBD, but qualitative correspondences are clear as demonstrated in Fig. . Very similar correlations are obtained using parameters appropriate for either PBE or PBE0, although the correlations are only qualitative (R 2 ∼ 0.6) and there are several significant outliers. Linear regression affords slopes ranging from 0.33-0.45, consistent with the much smaller values of the long-range dispersion correction as compared to a genuine dispersion energy, underscoring the conclusion that the numerical value of a +D or +MBD dispersion correction should not be equated with E disp . These are simply corrections to the DFT energy that improve the quality of potential energy surfaces for nonbonded systems, and are no less important ). Blue lines are linear regressions and best-fit equations are indicated. These fits include the five outliers shown in red, each of which corresponds to a system containing two hydrogen bonds and a short intermolecular distance: (acetic acid) 2 , (acetamide) 2 , (uracil) 2 in its base-pair geometry, (uracil)• • • (acetic acid), and (uracil)• • • (acetamide).