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Measurement of Ultrafast Vibrational Coherences in Polyatomic Radical Cations with Strong-Field Adiabatic Ionization
Published on: August 6, 2018
Structure effects in angle-resolved high-order above-threshold ionization of molecules
1State Key Laboratory of Magnetic Resonance and Atomic and Molecular Physics, Wuhan Institute of Physics and Mathematics, Chinese Academy of Sciences, Wuhan 430071, China.
Physical Review Letters
|September 28, 2010
Summary
Photoelectron angular distributions in above-threshold ionization (ATI) of N2 and O2 molecules reveal broader high-energy electron emission in O2 than N2. This difference is attributed to molecular orbital structure effects in strong-field ionization.
Area of Science:
- Strong-field physics
- Molecular quantum dynamics
- Atomic and molecular spectroscopy
Background:
- Above-threshold ionization (ATI) is a fundamental process in strong-field physics.
- Understanding electron emission dynamics in molecules is crucial for attosecond science.
- Previous studies have explored ATI in atoms and simple molecules, but molecular orbital effects remain an active area of research.
Purpose of the Study:
- To investigate energy-resolved photoelectron angular distributions in above-threshold ionization (ATI) of nonaligned N2 and O2 molecules.
- To analyze the high-energy cutoff region of ATI spectra, specifically at 10U(p) (ponderomotive energy).
- To elucidate the influence of molecular orbital structure on electron emission dynamics in strong laser fields.
Main Methods:
- Experimental measurement of energy-resolved angular distributions of photoelectrons from N2 and O2.
- Utilizing high-intensity, short laser pulses for above-threshold ionization.
- Theoretical analysis employing S-matrix theory and a semiclassical model.
Main Results:
- The photoelectron angular distribution at the plateau cutoff (10U(p)) was found to be broader for O2 compared to N2.
- This broadening in O2 suggests a more pronounced influence of its electronic structure on high-energy electron emission.
- The observed differences were successfully explained by considering the ground state molecular orbital structure.
Conclusions:
- The ground state molecular orbital structure significantly impacts high-energy electron emission in strong-field ionization.
- O2 exhibits broader photoelectron angular distributions at the ATI cutoff than N2 due to its specific orbital characteristics.
- This work provides insights into the role of molecular structure in complex strong-field phenomena.
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