Tailoring van der Waals dispersion interactions with external electric charges

Abstract

van der Waals (vdW) dispersion interactions strongly impact the properties of molecules and materials. Often, the description of vdW interactions should account for the coupling with pervasive electric fields, stemming from membranes, ionic channels, liquids, or nearby charged functional groups. However, this quantum-mechanical effect has been omitted in atomistic simulations, even in widely employed electronic-structure methods. Here, we develop a model and study the effects of an external charge on long-range vdW correlations. We show that a positive external charge stabilizes dispersion interactions, whereas a negative charge has an opposite effect. Our analytical results are benchmarked on a series of (bio)molecular dimers and supported by calculations with high-level correlated quantum-chemical methods, which estimate the induced dispersion to reach up to 35% of intermolecular binding energy (4 kT for amino-acid dimers at room temperature). Our analysis bridges electrostatic and electrodynamic descriptions of intermolecular interactions and may have implications for non-covalent reactions, exfoliation, dissolution, and permeation through biological membranes.

Understanding non-covalent interactions in larger molecular complexes from first principles

“…Given that the confinement of molecules is prevalent, this long-range repulsive term could be relevant to host-guest complexes where the guest molecule is confined in some way by the host. Second, an inhomogeneous electric field induced by a point charge located a few Ångstrom away from the center of mass of a molecular dimer can be used to tailor the vdW dispersion interaction between the molecules, i.e., to enhance or diminish the dispersion interaction depending on the sign of the external charge 50 . Such findings, taken together, provide strong evidence for the importance of higher-order (beyond second-order) interaction terms for the reliable and predictive description of intermolecular interactions in larger molecules in isolation and embedded in complex polarizable environments.…”

Theory and practice of modeling van der Waals interactions in electronic-structure calculations

“…362, for instance. Such contributions beyond dipolar coupling and/or second-order perturbation theory can introduce qualitatively new features in confined structures 362 or electric fields (also due to the presence of ionic species) 363 and the implications for realistic and practically relevant systems remain to be fully explored.…”

Advances in Density-Functional Calculations for Materials Modeling

“…A recent study using state-of-the-art DF calculations unraveled the origins of the difference between hydroxide and hydronium ion diffusion in water, attributing this difference to correlated proton transfer (135). In addition, ionic electrostatic fields can strongly affect intermolecular vdW interactions by making them either repulsive or attractive (136).…”