Noncovalent Interactions from Models for the Møller–Plesset Adiabatic Connection

Abstract

Given the omnipresence of noncovalent interactions (NCIs), their accurate simulations are of crucial importance across various scientific disciplines. Here we construct accurate models for the description of NCIs by an interpolation along the Møller–Plesset adiabatic connection (MP AC). Our interpolation approximates the correlation energy, by recovering MP2 at small coupling strengths and the correct large-coupling strength expansion of the MP AC, recently shown to be a functional of the Hartree–Fock density. Our models are size consistent for fragments with nondegenerate ground states, have the same cost as double hybrids, and require no dispersion corrections to capture NCIs accurately. These interpolations greatly reduce large MP2 errors for typical π-stacking complexes (e.g., benzene–pyridine dimers) and for the L7 data set. They are also competitive with state-of-the-art dispersion enhanced functionals and can even significantly outperform them for a variety of data sets, such as CT7 and L7.

The strong-interaction limit of density functional theory

“…Remark 2.10. (Nonsmoothness of optimal maps) The reader might wonder why, in SCE theory, no differentiability and not even continuity is imposed on the competing maps (the maps in the admissible class (35) are merely required to be measurable). This is because optimal maps, when they exist, are typically discontinuous.…”

“…They have been found to work reasonably well for interaction energies (especially of noncovalent systems) when Hartree-Fock orbitals (rather than KS ones) are used as input. This observation has triggered the study of the strong-interaction limit in Hartree-Fock theory [127,36], which, in turn, has lead to new interpolation schemes in this framework able to give very accurate results for a large variety of non-covalent interaction energies, ranging from small to medium-large systems [35].…”

Comparing correlation components and approximations in Hartree-Fock and Kohn-Sham theories via an analytical test case study

“…As a matter of fact, these approximations, developed within KS-DFT, have been successfully used with HF ingredients as a correction to the HF energy. [30][31][32][33] Such practice began from the simple heuristic observation that using ACMs on HF ingredients gave consistently better results than using them on KS ones. 30 While adaptations of the adiabatic connection approach to wavefunction methods had already begun to appear (see Ref.…”

Self-consistent Kohn-Sham calculations with adiabatic connection models

“…[33][34][35][36][37][38][39][40] Recently it has also been employed in the context of the Hartree-Fock (HF) theory 41 to develop corrections to the Møller-Plesset perturbation series. 42 The XC functionals based on ACMs have the general form…”

“…In the last years several ACMs have been tested for various chemical applications showing promising results, 44,45 especially in the description of non-covalent interactions. 42,46 Most of these recent studies have focused, however, on post-HF calculations while only little attention has been devoted to DFT-based ones. The main reason for this is that in the HF case the ACM is applied on top of the HF ground state, 41 which is a simple and well defined reference; on the contrary, in the DFT framework the ACM-based XC functional should be applied inside the KS equations in a self-consistent-field (SCF) fashion.…”