Van der Waals interactions: accuracy of pair potential approximations

Area of Science:

• Surface Science
• Atomic and Molecular Physics
• Condensed Matter Physics

Background:

• Van der Waals interactions are fundamental in describing atom-surface and molecule-surface interactions.
• Accurate modeling of these forces is crucial for understanding phenomena like adsorption and surface diffusion.
• A common approximation involves summing pairwise interactions between the adsorbate and surface atoms.

Purpose of the Study:

• To evaluate the accuracy of the pairwise interaction approximation for Van der Waals forces.
• To compare calculated potentials with established results across various system geometries.
• To extend the analysis to interactions involving diatomic and triatomic molecules.

Main Methods:

• Theoretical calculation of Van der Waals potentials.
• Comparison of approximated potentials with known theoretical and experimental data.
• Systematic analysis of interactions for single atoms, diatomic molecules, and triatomic molecules with surfaces and single atoms.

Main Results:

• The pairwise interaction approximation shows good agreement with known results for single atoms interacting with solids at large separations.
• The approximation's validity is confirmed across different geometries.
• Analogous findings are observed for diatomic and triatomic molecules, indicating the robustness of the method.

Conclusions:

• The pairwise summation method is a reliable approach for estimating Van der Waals interactions in the large separation regime.
• This approximation simplifies calculations while maintaining reasonable accuracy for various adsorbate types and surface configurations.
• The study provides confidence in using this method for further investigations in surface science and related fields.