The nature of three-body interactions in DFT: Exchange and polarization effects

Abstract

We propose a physically motivated decomposition of density functional theory (DFT) 3-body nonadditive interaction energies into the exchange and density-deformation (polarization) components. The exchange component represents the effect of the Pauli exclusion in the wave function of the trimer and is found to be challenging for density functional approximations (DFAs). The remaining density-deformation nonadditivity is less dependent upon the DFAs. Numerical demonstration is carried out for rare gas atom trimers, Ar-HX (X = F, Cl) complexes, and small hydrogen-bonded and van der Waals molecular systems. None of the tested semilocal, hybrid, and range-separated DFAs properly accounts for the nonadditive exchange in dispersion-bonded trimers. By contrast, for hydrogen-bonded systems, range-separated DFAs achieve a qualitative agreement to within 20% of the reference exchange energy. A reliable performance for all systems is obtained only when the monomers interact through the Hartree-Fock potential in the dispersion-free Pauli blockade scheme. Additionally, we identify the nonadditive second-order exchange-dispersion energy as an important but overlooked contribution in force-field-like dispersion corrections. Our results suggest that range-separated functionals do not include this component, although semilocal and global hybrid DFAs appear to imitate it in the short range.

Recent developments in symmetry‐adapted perturbation theory

“…The MP2+SDFT algorithm, which can be viewed as a three‐body generalization of the MP2C theory, was employed in a comparative study of several different three‐body dispersion expressions, to refine the lattice energy prediction for the benzene crystal, to investigate the cooperativity effects in model tetrel‐ and triel‐bonded trimers, and to examine the interactions of azaborines with two water molecules at once . Finally, nonadditive SAPT(DFT) benchmarks can shed light on the performance of DFT‐based methods for three‐body interaction energies, enabling the partitioning of the supermolecular three‐body DFT energy into exchange and deformation (polarization) terms …”

“…329 Finally, nonadditive SAPT(DFT) benchmarks can shed light on the performance of DFT-based methods for three-body interaction energies, enabling the partitioning of the supermolecular three-body DFT energy into exchange and deformation (polarization) terms. 330…”

Water Soluble Host–Guest Chemistry Involving Aromatic N-Oxides and Sulfonateresorcinarene

“…The attractive (or cooperativity-enhancing) effects are in "head-to-tail" → → → dipole arrangements (can be linear, circular or bent). The repulsive three-body polarization occurs in → → ← situations (also linear, circular, or bent) because the counteracting effect of the field-induced moments on the central system by the terminal ones [21,22]. This effect causes negative cooperativity and is strongly dependent on the magnitude of the central dipole.…”

Random-Phase Approximation in Many-Body Noncovalent Systems: Methane in a Dodecahedral Water Cage

“…In fact, approximate exchange functionals can deteriorate the threebody energies more than the missing description of three-body dispersion. 7,11,12 One way to improve the results is to use a scheme that does not approximate electron exchange, such as the random-phase approximation (RPA). RPA is based on the frequency-dependent density response function built from DFT orbitals and orbital energies.…”