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Measurement of Ultrafast Vibrational Coherences in Polyatomic Radical Cations with Strong-Field Adiabatic Ionization
Published on: August 6, 2018
Ultrafast hydrogen migration in acetylene cation driven by non-adiabatic effects
Mohamed El-Amine Madjet1, Zheng Li, Oriol Vendrell
1Center for Free-Electron Laser Science, DESY, Notkestrasse 85, D-22607 Hamburg, Germany. mohamed.el.amine.madjet@cfel.de
The Journal of Chemical Physics
|March 15, 2013
Summary
Investigating acetylene cation dynamics reveals photoionization induces a structural change. Hydrogen migration follows non-radiative relaxation, leading to oscillations between acetylene and vinylidene states.
Area of Science:
- Physical Chemistry
- Chemical Physics
- Computational Chemistry
Background:
- Acetylene cation dynamics are crucial for understanding molecular reactions.
- Non-adiabatic effects significantly influence molecular structure and reactivity.
- Mixed quantum-classical methods are essential for simulating complex molecular systems.
Purpose of the Study:
- To investigate the non-adiabatic dynamics of the acetylene cation.
- To compare Tully's fewest switches and Landau-Zener surface hopping methods.
- To elucidate the pathways of structural change and hydrogen migration.
Main Methods:
- Mixed quantum-classical dynamics simulations.
- Trajectory surface hopping methods (Tully's fewest switches and Landau-Zener).
- Analysis of correlation functions to identify dynamic processes.
Main Results:
- Photoionization drives the acetylene cation from a linear to a trans-bent structure.
- Conical intersections facilitate relaxation to ground state acetylene or vinylidene.
- Hydrogen migration consistently occurs after non-radiative electronic relaxation.
- Coherent oscillations between acetylene and vinylidene observed with a ~70 fs period.
Conclusions:
- Non-adiabatic dynamics play a key role in acetylene cation rearrangement.
- The choice of surface hopping method impacts the simulation results.
- Understanding these dynamics is vital for predicting chemical reaction outcomes.
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