Does Hartree-Fock density functional theory work through error cancellation for the interaction energies of halogen and chalcogen bonded systems?

Semi-local functionals are often more accurate for energies when evaluated on the Hartree-Fock (HF) density than on their own self-consistent densities. HF densities are known to greatly reduce or overcorrect the charge-delocalization error associated with semi-local functionals. Over the last decade, this Hartree-Fock density functional theory (HF-DFT) has been systematized as density corrected DFT (DC-DFT) [1]. For reaction barriers [2,3] and binding energies of water clusters [3,4], HF-DFT seems to work through a cancellation of negative functional-driven error by positive density-driven error. In this work, we present evidence that the success [5] of HF-DFT for the B30 test set of weakly-bonded molecular complexes results from a similar error cancellation. For most of the complexes we employ proxies for the exact densities: the r2SCAN50 local hybrid, the LC-ω-PBE long-range-corrected hybrid, and FLOSIC, the Fermi-Löwdin orbital self-interaction correction [6], and for one (NH₃…ClF) we employ a Kohn-Sham inversion of the CCSD(T) density.

[1] S. Vuckovic et al., J. Chem. Theory Comput. 15, 6636 (2019).

[2] A.D. Kaplan et al., J. Chem. Theory Comput. 19, 532 (2023).

[3] B. Kanungo. et al., J. Phys. Chem. Letters 15, 323 (2024).

[4] A.D. Kaplan et al., J. Chem. Theory Comput. 20, 5517 (2024).

[5] Y. Kim et al., J. Phys. Chem. Lett. 10, 295 (2019).

[6] M.R. Pederson et al., J. Chem .Phys. 140, 121103 (2014).