A first-principles-based correlation functional for harmonious connection of short-range correlation and long-range dispersion

TL;DR

This paper introduces a physically motivated meta-GGA correlation functional that seamlessly integrates short-range correlation with long-range dispersion corrections, reducing double-counting and improving accuracy for non-covalent interactions.

Contribution

A new correlation functional based on constraint satisfaction that can be combined with dispersion corrections without double-counting, enhancing the accuracy of non-covalent interaction predictions.

Findings

Functional performs well with DFT-D3 dispersion correction.

Predictions compare favorably with reference energies.

Minimal empiricism allows flexible blending with dispersion models.

Abstract

We present a physically motivated correlation functional belonging to the meta-generalized gradient approximation (meta-GGA) rung, which can be supplemented with long-range dispersion corrections without introducing double-counting of correlation contributions. The functional is derived by the method of constraint satisfaction, starting from an analytical expression for a real-space spin-resolved correlation hole. The model contains a position-dependent function that controls the range of the interelectronic correlations described by the semilocal functional. With minimal empiricism, this function may be adjusted so that the correlation model blends with a specific dispersion correction describing long-range contributions. For a preliminary assessment, our functional has been combined with the DFT-D3 dispersion correction and full Hartree-Fock (HF)-like exchange. Despite the HF-exchange approximation, its predictions compare favorably with reference interaction energies in an extensive set of non-covalently bound dimers.