Strong field electron emission from fixed in space H(2)(+) ions

Area of Science:

• Atomic and Molecular Physics
• Quantum Dynamics
• Laser-Matter Interactions

Background:

• Investigating electron emission from molecular ions under intense laser fields is crucial for understanding fundamental light-matter interactions.
• Existing models, like quasistatic enhanced ionization, may not fully capture the complex dynamics in molecular systems.

Purpose of the Study:

• To experimentally probe electron emission from the H(2)(+) ion using a circularly polarized laser pulse.
• To compare experimental electron momentum distributions with theoretical predictions from the time-dependent Schrödinger equation.
• To elucidate the underlying electron dynamics responsible for the observed momentum distributions.

Main Methods:

• Experimental study of electron emission from H(2)(+) using a circularly polarized laser pulse (800 nm, 6×10^14 W/cm^2).
• Coincident detection of electrons and protons to obtain the electron momentum distribution in the body-fixed frame.
• Theoretical analysis using a two-dimensional time-dependent Schrödinger equation.

Main Results:

• Experimental electron momentum distributions were obtained and compared with theoretical calculations.
• Observed radial and angular distributions deviate significantly from the predictions of the quasistatic enhanced ionization model.
• An unexpected electron momentum distribution was identified, suggesting complex laser-driven electron dynamics within the molecule.

Conclusions:

• The study reveals that complex laser-driven electron dynamics within the H(2)(+) ion significantly influence the ionization process.
• The timing of ionization and the initial electron momentum are affected by these internal dynamics, leading to deviations from simplified models.
• This work highlights the need for more sophisticated theoretical approaches to accurately describe electron emission from molecules in intense laser fields.