Two-pulse control over double ionization pathways in CO2.

Area of Science:

• Physical Chemistry
• Quantum Dynamics
• Molecular Physics

Background:

• Sequential double ionization (SDI) is crucial for understanding molecular fragmentation.
• Controlling molecular dynamics with tailored laser pulses is a key challenge in physical chemistry.

Purpose of the Study:

• To visualize and control molecular dynamics during CO2 sequential double ionization.
• To identify and manipulate vibronic dynamics in CO2(+) intermediates.
• To demonstrate pathway control in CO2(2+) formation via laser pulse sequencing.

Main Methods:

• Utilizing a sequence of two time-delayed laser pulses with varying peak intensities.
• Measuring fragment ion yields (CO2(2+), CO(+)/O(+)) as a function of pulse delay.
• Applying Fourier analysis to identify underlying vibronic dynamics.

Main Results:

• Weak modulations in ion yields were observed, attributed to vibronic dynamics in CO2(+).
• Fourier analysis identified two primary double ionization pathways.
• Reversing the laser pulse sequence enabled control over the ionization pathway selection.
• Modulating vibronic dynamics were found to oscillate out-of-phase.

Conclusions:

• Laser pulse sequencing offers a method to control molecular dynamics and ionization pathways.
• Out-of-phase vibronic dynamics provide opportunities for extended timescale strong-field fragmentation control.
• This study advances the understanding of molecular interactions with intense laser fields.