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High-energy molecular-frame photoelectron angular distributions: a molecular bond-length ruler
I Vela-Peréz1, F Ota2, A Mhamdi3
1Institut für Kernphysik, Goethe-Universität, Max-von-Laue-Straße 1, 60438 Frankfurt am Main, Germany.
Physical Chemistry Chemical Physics : PCCP
|May 9, 2023
Summary
We discovered a universal formula linking molecular bond length to photoelectron angular distribution (MFPAD) tilt angles. This finding aids in analyzing molecular structures using synchrotron light, particularly for molecules like CO and N2.
Area of Science:
- Atomic and Molecular Physics
- Quantum Chemistry
- Spectroscopy
Background:
- Molecular-frame photoelectron angular distributions (MFPADs) provide detailed insights into molecular electronic structure and dynamics.
- Previous studies have explored MFPADs, but a direct, universal link to molecular geometry was lacking.
Purpose of the Study:
- To establish a simple, universal formula connecting MFPAD forward-scattering peak tilt angles to molecular bond lengths.
- To validate this formula using experimental and computational data for small molecules.
Main Methods:
- Utilizing circularly polarized synchrotron light to probe small molecules.
- Analyzing molecular-frame photoelectron angular distributions (MFPADs).
- Applying a derived formula to experimental and ab initio calculated MFPADs of CO and considering N2.
Main Results:
- A slight tilt of the main forward-scattering peaks in MFPADs relative to the molecular axis was observed.
- This tilt angle is directly proportional to the molecular bond length via a derived universal formula.
- The formula was successfully applied to C 1s and O 1s photoelectrons of CO.
Conclusions:
- The developed formula offers a straightforward method for determining molecular bond lengths from MFPADs.
- This approach enhances the utility of MFPADs in molecular structure determination.
- The study also highlights the impact of back-scattering contributions in homonuclear molecules like N2.
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