Computational investigations of dispersion interactions between small molecules and graphene-like flakes

TL;DR

This study compares high-level and DFT methods for modeling dispersion interactions between small molecules and graphene-like surfaces, highlighting the importance of correction methods and challenges with system size.

Contribution

It provides a comprehensive assessment of dispersion modeling techniques and introduces novel coupled-cluster quality interaction curves for large carbon flakes.

Findings

D3 correction is essential for meaningful results.

Little difference between commonly used functionals without correction.

Empirically-corrected DFT struggles with larger systems.

Abstract

In this work, we investigate dispersion interactions in a selection of atomic, molecular, and molecule-surface systems, comparing high-level correlated methods with empirically-corrected density functional theory (DFT). We assess the efficacy of functionals commonly used for surface-based calculations, with and without the D3 correction of Grimme. We find that the inclusion of the correction is essential to get meaningful results, but there is otherwise little to distinguish between the functionals. We also present coupled-cluster quality interaction curves for \ce{H2} and \ce{NO2} interacting with large carbon flakes, acting as models for graphene surfaces, using novel absolutely localised molecular orbital based methods. These calculations demonstrate that the problems with empirically-corrected DFT when investigating dispersion appear to compound as the system size increases, with important implications for future computational studies of molecule-surface interactions.