Figure plots torsional energy profiles of rubrene and some fluorinated derivatives thereof, along the ∠C 1 -C 2 -C 3 -C 4 angle that is indicated in Fig. . (The fluorinated derivatives have been suggested as a means of tuning the noncovalent interactions and therefore the crystal structure, modulating the band gap, or to enhance stability with respect to oxidation. ) We refer to "planar" versus "twisted" configurations in Fig. with respect to the core tetracene unit. As noted in previous work, twist angles 30 • can increase conjugation, by bringing the π electrons of the aromatic side chains into play, and common density functionals thus overstabilize twisted orientations relative to planar ones, even while the twisted configuration is more stable according to CCSD(T) calculations. In the case of the SCAN+D3 functional, DC-DFT improves the relative conformational energies of the planar (0 • ) and fully-twisted (60 • ) structures by 2-4 kJ/mol, although the twisted conformation is still somewhat overstabilized even with DC-DFT. This remains the case for the B3LYP+D3 and PBE0+D3 functionals also; see Fig. . With the SCAN0+D3 functional, DC-DFT improves the relative energies of the fully-twisted structures, and these energies match quite well with the CCSD(T) benchmark for the two out of three derivatives; see Figs.