Measuring Charge Transfer between Adsorbate and Metal Surfaces.

Area of Science:

• Surface Science
• Materials Chemistry
• Atomic Physics

Background:

• Charge transfer between dissimilar atoms is crucial for chemical reactions like corrosion and catalysis.
• Directly observing this charge transfer has historically been difficult.
• Understanding these interactions is key to controlling chemical processes at interfaces.

Purpose of the Study:

• To demonstrate a novel method for probing charge transfer between adsorbates and metal surfaces.
• To utilize synchrotron-based ambient pressure X-ray photoelectron spectroscopy (AP-XPS) for this purpose.
• To investigate the oxygen-copper system as a model for charge transfer monitoring.

Main Methods:

• Employing synchrotron-based ambient pressure X-ray photoelectron spectroscopy (AP-XPS).
• Analyzing the Auger process resulting from oxygen chemisorption on copper (Cu) surfaces.
• Combining experimental data with ab initio calculations.

Main Results:

• Oxygen chemisorption on Cu surfaces induces a distinct Auger process, different from the Coster-Kroning transition.
• This chemisorption-induced Auger process can quantify the degree of charge transfer.
• The method provides a direct probe of charge dynamics at the atomic level.

Conclusions:

• Synchrotron-based AP-XPS can effectively monitor charge transfer between adsorbates and metal surfaces.
• The identified chemisorption-induced Auger process serves as a fingerprint for bond formation.
• This approach has broad implications for studying and controlling interfacial chemical processes.