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Figure 10
Total interaction energies Etot (kcal mol−1), electrostatic contributions Ees (kcal mol−1) to total interaction energies, and electrostatic energies computed from point molecular charges ECoul (kcal mol−1) for the AA1 dimers extracted from (a) the CC and (b) the ACH experimental crystal structures as a function of donor⋯acceptor distance (Å), simulating the dissociation curve along hydrogen bonding. Etot (theo,gas) and Ees (theo,gas) are the energies according to the DFT-SAPT method applied to dimers of molecules bearing formal +1 e charge; Etot (exp,crystal) and Ees (exp,crystal) are the energies from DFT-SAPT after rough correction taking into account the partial molecular charge observed from experiment; Etot (neutral) and Ees (neutral) are the energies from DFT-SAPT after complete removal of electrostatic repulsion due to the presence of molecular charge; and ECoul are the energies computed from various point molecular charges placed at the centres of molecular mass: +1 e (theo,gas), experimental charge (exp,crystal), 0 e (neutral). Dark-blue and red crosses denote Etot (theo,gas) and Ees (theo,gas) DFT-SAPT energies, respectively, computed for geometries taken from dimer geometry optimization and transition state search in the gas phase.

IUCrJ
Volume 5| Part 4| July 2018| Pages 449-469
ISSN: 2052-2525
https://doi.org/10.1107/S2052252518006346