Testing the pairwise additive potential approximation using DFT: coadsorption of CO and N on Rh (100)

Area of Science:

• Surface Science
• Physical Chemistry
• Computational Materials Science

Background:

• Adsorbate-adsorbate interactions are crucial for surface science, impacting surface process thermodynamics and kinetics.
• Pairwise additive potentials are commonly used to model these interactions in simulations like temperature-programmed desorption (TPD).

Purpose of the Study:

• To validate the accuracy of pairwise additive potentials against density functional theory (DFT) calculations for adsorbate interactions.
• To investigate the necessity of higher-order interaction terms (three-body or more) in modeling adsorption energy perturbations.
• To establish a direct link between DFT-derived microscopic configurations and observed TPD desorption features.

Main Methods:

• Utilizing density functional theory (DFT) to calculate interaction energies between coadsorbed species.
• Comparing DFT-calculated energies with those obtained from pairwise additive potential models.
• Analyzing temperature-programmed desorption (TPD) spectra and correlating features with DFT results.

Main Results:

• The pairwise additive potential approximation was confirmed as a reliable method for representing adsorbate-adsorbate interactions.
• Inclusion of three-body or higher-order interaction terms was found to be unnecessary for estimating adsorption energy perturbations.
• DFT calculations successfully explained and elucidated the microscopic origins of features observed in TPD experiments.

Conclusions:

• Pairwise additive potentials are sufficient for accurately modeling adsorbate interactions and TPD spectra, simplifying computational approaches.
• DFT provides a powerful tool for interpreting TPD data, bridging macroscopic observations with microscopic surface phenomena.