Tailoring van der Waals dispersion interactions with external electric charges

Area of Science:

• Physical Chemistry
• Computational Chemistry
• Molecular Biophysics

Background:

• Van der Waals (vdW) dispersion interactions are crucial for molecular and material properties.
• These interactions are often influenced by electric fields from environments like membranes or charged groups.
• Current atomistic simulations, including electronic-structure methods, often neglect this charge-dispersion coupling.

Purpose of the Study:

• To develop a model for studying the effects of external charges on long-range vdW correlations.
• To investigate how external charges modulate intermolecular dispersion interactions.
• To quantify the impact of induced dispersion on binding energies.

Main Methods:

• Development of a new theoretical model for charge-perturbed vdW interactions.
• Analytical calculations of charge effects on dispersion.
• Benchmarking against high-level correlated quantum-chemical methods.
• Application to (bio)molecular dimers.

Main Results:

• A positive external charge was found to stabilize vdW dispersion interactions.
• A negative external charge was shown to destabilize vdW dispersion interactions.
• Induced dispersion can account for up to 35% of intermolecular binding energy, significant for biological systems (e.g., 4kT for amino-acid dimers).

Conclusions:

• The study bridges electrostatic and electrodynamic descriptions of intermolecular forces.
• The findings highlight the importance of considering charge-dispersion coupling in simulations.
• Implications for understanding non-covalent reactions, material properties, and transport through biological membranes.