As explained in Section 3 .3, we have tested not only the traditional augmented Karlsruhe basis sets (def2-SVPD, etc.) but also heavy-augmented versions (def2ha-SVP, etc.) in which diffuse functions are removed from the hydrogen atoms, and minimally-augmented versions (def2-ma-SVP, etc.) that further remove the diffuse functions having highest angular momentum on the other atoms. Finally, the def2-SVP, def2-TZVP, and def2-QZVP basis sets contain no diffuse functions whatsoever.