Many-body van der Waals interactions beyond the dipole approximation.

Area of Science:

• Computational chemistry
• Materials science
• Condensed matter physics

Background:

• Long-ranged van der Waals (vdW) interactions are fundamental in molecular and nanoscale systems.
• Current models, like Lennard-Jones, often rely on two-body and dipolar approximations.
• The combined effects of beyond-dipole interactions and many-body contributions remain poorly understood, particularly for large systems.

Purpose of the Study:

• To develop and present a full many-body description of van der Waals (vdW) interactions that extends beyond the dipole approximation.
• To create a method efficiently applicable to large-scale molecular and nanoscale systems.
• To investigate the interplay between multipolar terms and many-body effects in vdW interactions.

Main Methods:

• Development of a theoretical framework for many-body van der Waals interactions.
• Inclusion of beyond-dipole terms, specifically dipole-quadrupole interactions.
• Application of the method to large-scale molecular and nanoscale systems.
• Analysis of many-body screening effects on vdW interactions.

Main Results:

• Dipole-quadrupole interactions are shown to be significant even at nanometer-scale separations.
• Many-body effects introduce system-dependent screening, substantially reducing vdW interactions.
• The developed many-body, multipolar approach provides a more accurate description compared to traditional methods.
• The findings highlight the importance of considering both many-body and multipolar effects concurrently.

Conclusions:

• A complete many-body description beyond the dipole approximation is essential for accurate vdW interaction calculations.
• Combined many-body and multipolar terms are critical for understanding vdW forces in complex molecular and nanoscale systems.
• This work offers a reliable computational tool for investigating vdW interactions in systems previously challenging to model.