Quantum state-resolved gas/surface reaction dynamics probed by reflection absorption infrared spectroscopy.

Area of Science:

• Surface science
• Physical chemistry
• Spectroscopy

Background:

• Gas/surface reaction dynamics are crucial in chemistry and materials science.
• Understanding reaction mechanisms at the quantum level requires advanced experimental techniques.
• Current methods may lack the resolution for detailed state-resolved studies.

Purpose of the Study:

• To design and characterize a novel molecular-beam/surface-science apparatus.
• To enable quantum state-resolved studies of gas/surface reaction dynamics.
• To utilize Reflection Absorption Infrared Spectroscopy (RAIRS) for product detection.

Main Methods:

• Combines optical state-specific reactant preparation via rapid adiabatic passage in a molecular beam.
• Employs RAIRS for non-invasive, online monitoring of surface-bound reaction products.
• Calibrated RAIRS detection provides product uptake rates and coverage-dependent reaction probabilities S(θ).

Main Results:

• The apparatus facilitates detailed, quantum state-resolved investigations of surface reactions.
• RAIRS provides structural information on adsorbed products, aiding in pathway and branching ratio determination.
• Demonstrated utility through studies of methane dissociative chemisorption on Pt(111).

Conclusions:

• The developed apparatus and RAIRS detection offer unprecedented detail in studying gas/surface reactions.
• This technique advances the understanding of reaction mechanisms, product identification, and kinetics.
• Enables precise determination of state-resolved reaction probabilities and reaction pathway branching.