Two-bath model for activated surface diffusion of interacting adsorbates

Area of Science:

• Surface science
• Physical chemistry
• Computational physics

Background:

• Adsorbate diffusion and vibrational motions are crucial in surface phenomena.
• Existing models may not fully capture complex interactions at low to moderate coverages.
• Understanding these dynamics is key for catalysis and materials science.

Purpose of the Study:

• To introduce and validate a purely stochastic model for adsorbate dynamics.
• To account for thermal surface phonons and adsorbate-adsorbate collisions.
• To apply the model to specific adsorbate-surface systems.

Main Methods:

• Development of the interacting single adsorbate model.
• Utilizing a two-bath model generalizing the Caldeira-Leggett Hamiltonian.
• Incorporating uncorrelated noise functions for phonons and collisions.
• Application to sodium (Na) atom diffusion on a copper (Cu(001)) surface.

Main Results:

• The model effectively describes diffusion and low vibrational motions for coverages up to approximately 0.12.
• Thermal surface phonons and adsorbate-adsorbate collisions are successfully integrated.
• The model provides a robust framework for analyzing adsorbate-surface interactions.

Conclusions:

• The interacting single adsorbate model offers a powerful tool for studying surface dynamics.
• The stochastic approach provides accurate predictions for low-moderate coverage regimes.
• This work advances the understanding of adsorbate behavior on metal surfaces.