CT → 0 in the CBS limit, where there is no difference between monomer and dimer basis sets. A numerical demonstration is provided in Fig. using the the prototypical Lewis acid/base system H 3 N• • • BH 3 (borazane) and extending previously reported data 153 to basis sets up to aug-cc-pV7Z. Alternatively, one may isolate E CT via a regularization procedure that removes the Coulomb driving force that attracts electrons on A to monomer B. CT is defined in Eq. ( ) and might be evaluated with or without the δHF correction.