Observation of orientation-dependent electron transfer in molecule-surface collisions

Area of Science:

• Surface Science
• Chemical Physics
• Materials Chemistry

Background:

• Efficient molecular energy transfer and reactions depend on specific relative molecular orientations.
• Surface reactions, particularly those involving electron transfer during adsorption, can be significantly faster than gas-phase reactions, highlighting the importance of surfaces in catalysis.
• The vibrational relaxation of nitric oxide (NO) is an example of energy transfer driven by electron transfer.

Purpose of the Study:

• To investigate the influence of molecular orientation on electron transfer-driven vibrational relaxation at a surface.
• To explore steric effects in surface-mediated electron transfer reactions using NO on Au(111).

Main Methods:

• Experimental investigation of nitric oxide (NO) vibrational relaxation upon interaction with an Au(111) surface.
• Analysis of energy transfer dynamics influenced by the orientation of the NO molecule relative to the surface.

Main Results:

• Vibrational relaxation of NO is dramatically enhanced when the nitrogen atom is oriented toward the Au(111) surface.
• This orientation-dependent enhancement indicates significant steric influence on the electron transfer process.

Conclusions:

• The study demonstrates that molecular orientation plays a crucial role in surface-catalyzed electron transfer reactions.
• This work provides a rare experimental insight into the steric control of electron transfer reactions at surfaces.