Assessment of SAPT(DFT) with meta-GGA functionals

Michał Hapka,Grzegorz Chałasiński,Marcin Modrzejewski,Małgorzata M. Szczęśniak

doi:10.1007/s00894-020-4340-9

Abstract

This work examines the suitability of meta-GGA functionals for symmetry-adapted perturbation theory (SAPT) calculations. The assessment is based on the term-by-term comparison with the benchmark SAPT variant based on coupled-cluster singles and doubles description of monomers, SAPT(CCSD). Testing systems include molecular complexes ranging from strong to weak and the He dimer. The following nonempirical meta-GGAs are examined: TPSS, revTPSS, MVS, SCAN, and SCAN0 with and without the asymptotic correction (AC) of the exchange-correlation potential. One range-separated meta-GGA functional, LC-PBETPSS, is also included. The AC-corrected pure meta-GGAs (with the exception of MVS) represent a definite progress in SAPT(DFT) compared to pure GGA, such as PBEAC, with their more consistent predictions of energy components. However, none of the meta-GGAs is better than the hybrid GGA approach SAPT(PBE0AC). The SAPT(DFT) electrostatic energy offers the most sensitive probe of the quality of the underlying DFT density. Both SCAN- and TPSS-based electrostatic energies agree with reference to within 5% or better which is an excellent result. We find that SCAN0 can be used in SAPT without the AC correction. The long-range corrected LC-PBETPSS is a reliable performer both for the components and total interaction energies.

Highlights

Symmetry-adapted perturbation theory (SAPT) is an effective means of computing the interaction energies of non-covalent interactions with direct insights into their composition [1]
To what extent satisfying these constraints helps in SAPT(DFT) was our question in this paper
The correct potential asymptote can be secured in two ways: either by using an asymptotic correction, for example, of the gradient-regulated asymptotic correction (GRAC) type, or by employing a long-range correction via the range separation of electron-electron interactions

Summary

Introduction

Symmetry-adapted perturbation theory (SAPT) is an effective means of computing the interaction energies of non-covalent interactions with direct insights into their composition [1]. If the density functional theory (DFT) were to be used for describing the monomer wave functions, the intrasystem correlation effects can be captured (at least in principle) giving rise to the simplest way of bypassing double perturbation SAPT expansion. Meta-GGA exchange-correlation energies depend on kinetic energy density, τ, in addition to density and its gradient as GGAs do This gives them more functional flexibility to satisfy a larger number of exact constraints. It is interesting if this ability reflects on density functional’s performance in SAPT Another way of incorporating meta-GGA ingredients is through the range-separation procedure build on the Becke-Roussel exchange hole [24] that includes both τ and the Laplacian of density. We include one such functional, LC-PBETPSS, designed using the range-separation method proposed in Ref. This results from the error compensation due to systematic underestimation of all the energy contributions

Method

Findings

Summary and conclusions