Halogen and structure sensitivity of halobenzene adsorption on copper surfaces
Christina Schunke1, Daniel P Miller2, Eva Zurek3
1Ruhr-Universität Bochum, Lehrstuhl für Physikalische Chemie I, Universitässtraße 150, D-44803 Bochum, Germany. Christina.Schunke@rub.de.
Physical Chemistry Chemical Physics : PCCP
|February 3, 2022
Summary
Controlling molecular orientation on surfaces is key for reactivity. This study shows how halogen type and surface structure dictate whether halogenated benzenes lie flat or tilt, impacting their chemical behavior.
Area of Science:
- Surface Science
- Physical Chemistry
- Materials Science
Background:
- Molecular adsorption orientation significantly impacts surface reactivity.
- Tailoring these orientations is crucial but challenging.
- Understanding molecule-surface and molecule-molecule interactions is key.
Purpose of the Study:
- To investigate how substituents (halogens) and surface structure affect adsorption orientation.
- To determine the transition from parallel to tilted adsorption for halogenated benzenes.
- To elucidate the role of intermolecular and molecule-surface forces.
Main Methods:
- Utilizing the surface selection rule in reflection-absorption infrared spectroscopy (RAIRS).
- Studying bromo-, chloro-, and fluorobenzene adsorption on Cu(111) and Cu(110) surfaces.
- Analyzing adsorption orientation at varying coverages.
Main Results:
- On Cu(111), molecules adsorb parallel at low coverage, tilting at higher coverages with varying thresholds.
- On Cu(110), bromo- and chlorobenzene follow this trend with lower thresholds.
- Fluorobenzene tilts at low coverages on Cu(110), unlike on Cu(111).
Conclusions:
- Halogen type and surface structure significantly influence adsorption orientation.
- Adsorption behavior results from an interplay of molecule-molecule and molecule-surface interactions.
- Findings are relevant for controlling two-dimensional surface reactivity.
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