Effective screening of medium-assisted van der Waals interactions between embedded particles.

Area of Science:

• Physical Chemistry
• Quantum Mechanics
• Materials Science

Background:

• Dispersive interactions, like van der Waals forces, are fundamental to molecular behavior.
• Understanding these interactions in different media is essential for predicting material properties and chemical reactivity.
• Existing models often simplify or neglect the influence of the surrounding environment.

Purpose of the Study:

• To investigate and quantify the effect of an implicit medium on dispersive interactions.
• To derive simple expressions for the screening of van der Waals coefficients.
• To provide practical models and parameters for common solvents and molecules.

Main Methods:

• Derivation of analytical expressions for the correction to vacuum van der Waals C6-coefficients.
• Application of a single-point Gauss quadrature approximation.
• Evaluation of environmental permittivity near resonance frequencies.

Main Results:

• The vacuum van der Waals C6-coefficient is screened by the permittivity squared of the environment.
• This screening is most accurate when the medium is transparent near the interacting particles' resonance frequencies.
• Simple models and parameters are provided for various solvents, atoms, and small molecules.

Conclusions:

• The proposed method offers an intuitive and computationally efficient way to account for medium effects on dispersive interactions.
• The findings are particularly relevant for transparent media and provide a valuable tool for computational chemistry and materials science.
• The developed models facilitate the study of intermolecular forces in condensed phases.