Predicting C-H/$\pi$ interactions with nonlocal density functional theory

TL;DR

This paper evaluates a new nonlocal density functional for predicting C-H/$$ interactions, showing it outperforms traditional functionals in accuracy and computational efficiency for modeling noncovalent aromatic interactions.

Contribution

The study introduces and assesses a novel nonlocal density functional that improves prediction accuracy of C-H/$ interactions compared to traditional functionals.

Findings

Interaction energies agree well with coupled-cluster results

Equilibrium distances are overpredicted with revPBE exchange

Functional accurately predicts effects of halogen substituents

Abstract

We examine the performance of a recently developed nonlocal density functional in predicting a model noncovalent interaction, the weak bond between an aromatic $\pi$ system and an aliphatic C-H group. The new functional is a significant improvement over traditional density functionals, providing results which compare favorably to high-level quantum-chemistry techniques but at considerably lower computational cost. Interaction energies in several model C-H/$\pi$ systems are in generally good agreement with coupled-cluster calculations, though equilibrium distances are consistently overpredicted when using the revPBE functional for exchange. The new functional correctly predicts changes in energy upon addition of halogen substituents.