Rotation and diffusion of naphthalene on Pt(111)

Area of Science:

• Surface Science
• Physical Chemistry
• Materials Science

Background:

• Understanding molecule-surface interactions is crucial for catalysis and nanotechnology.
• Naphthalene adsorption on metal surfaces is a fundamental system for studying molecular behavior.

Purpose of the Study:

• To investigate the adsorption, diffusion, and rotation dynamics of naphthalene on Pt(111) surfaces.
• To compare experimental findings with theoretical calculations for accurate energy barrier determination.

Main Methods:

• Variable temperature scanning tunneling microscopy (STM) experiments.
• Van der Waals-enabled density functional theory (DFT) calculations.
• Automated mapping of diffusion pathways.

Main Results:

• Naphthalene exhibits facile on-site rotation with a low experimental barrier (0.69 eV).
• Diffusion to neighboring sites is more energetically demanding than rotation.
• Theoretical calculations (DFT) confirm experimental observations, with rotation barriers of 0.75 eV and translation barriers of 0.78 eV.
• Automated pathway mapping revealed intricate diffusion routes with numerous local minima.

Conclusions:

• Naphthalene's rotational mobility on Pt(111) is significantly higher than its translational mobility.
• The combination of STM and DFT provides a detailed understanding of molecule-substrate interactions.
• Automated computational methods enhance the discovery of complex diffusion mechanisms.