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Methods of Ex Situ and In Situ Investigations of Structural Transformations: The Case of Crystallization of Metallic Glasses
Published on: June 7, 2018
X-ray emission spectroscopy and density functional study of CO/Fe(100)
1Department of Physics, AlbaNova University Center, Stockholm University, SE-106 91 Stockholm, Sweden.
The Journal of Chemical Physics
|January 28, 2012
Summary
We studied carbon monoxide (CO) bonding on iron surfaces using spectroscopy. The "lying down" CO on hollow sites involves charge transfer, while "on-top" CO is tilted due to interactions.
Area of Science:
- Surface Science
- Materials Chemistry
- Physical Chemistry
Background:
- Understanding adsorbate-surface interactions is crucial for catalysis.
- Carbon monoxide (CO) adsorption on transition metals is a fundamental system.
- Different binding sites and coverages lead to varied electronic structures.
Purpose of the Study:
- To investigate the electronic structure of CO adsorbed on Fe(100) at different sites and coverages.
- To elucidate the bonding mechanisms of CO in the α(3) (hollow) and α(1) (on-top) phases.
- To compare experimental findings with theoretical calculations.
Main Methods:
- X-ray emission spectroscopy (XES)
- X-ray absorption spectroscopy (XAS)
- Density Functional Theory (DFT) calculations
Main Results:
- The electronic structure of hollow-site CO (α(3) phase) was analyzed, revealing "lying down" bonding.
- On-top CO in the high-coverage α(1) phase was found to be tilted due to adsorbate-adsorbate interactions.
- DFT calculations supported the experimental observations of bonding and structure.
Conclusions:
- The bonding of hollow-site CO involves significant π to π* charge transfer, including interaction at the oxygen atom.
- On-top CO bonding, despite tilting, retains characteristics of vertical adsorption seen on other transition metals.
- The study provides detailed insights into CO electronic structure and bonding on Fe(100).
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