Orbital specific chemistry: controlling the pathway in single-molecule dissociation

Area of Science:

• Surface science
• Chemical physics
• Nanotechnology

Background:

• Chemisorption of molecules on metal surfaces is fundamental to catalysis.
• Understanding dissociation pathways is key to controlling chemical reactions at the nanoscale.

Purpose of the Study:

• To investigate the control of single oxygen molecule (O2) dissociation pathways on a silver surface using a scanning tunneling microscope (STM).
• To correlate electron tunneling dynamics with the resulting adsorbed oxygen atom configurations.

Main Methods:

• Utilized a scanning tunneling microscope (STM) at low temperatures (13 K) to manipulate single O2 molecules on a Ag(110) surface.
• Controlled electron tunneling (inward or outward) from the STM tip to induce molecular dissociation.

Main Results:

• Electron tunneling into the O2 molecule resulted in dissociation and O atom separation along the [110] direction.
• Electron ejection from the O2 molecule led to O atom separation along the [001] direction.
• Demonstrated directional control over dissociation products based on electron transfer direction.

Conclusions:

• The dissociation pathway and product formation of O2 on Ag(110) can be precisely controlled by electron tunneling.
• A specific molecular orbital at the Fermi level dictates the outcome of the dissociation process.