Subcycle controlled charge-directed reactivity with few-cycle midinfrared pulses

Area of Science:

• Quantum dynamics
• Molecular physics
• Laser-matter interactions

Background:

• Controlling electron motion with laser light offers potential for directing chemical reactions.
• The short duration of optical cycles limits control over fast molecular dissociation reactions.

Purpose of the Study:

• To overcome limitations in controlling molecular reactions by extending laser control metrology to the mid-infrared spectrum.
• To investigate the dissociative ionization of deuterium molecules (D2) using waveform-controlled 2.1 μm laser light.

Main Methods:

• Utilizing waveform-controlled few-cycle laser pulses in the mid-infrared (2.1 μm).
• Studying the prototypical dissociative ionization of deuterium molecules (D2).
• Performing quantum-dynamical calculations to analyze dissociation pathways and control mechanisms.

Main Results:

• Observed pronounced subcycle control of directional D(+) ion emission from D2 fragmentation.
• Demonstrated unprecedented charge-directed reactivity.
• Simultaneously observed and controlled two distinct reaction pathways exhibiting directional ion emission for the first time.

Conclusions:

• Mid-infrared laser control enables precise steering of electron motion and molecular fragmentation.
• Subcycle control of dissociative ionization is achievable, opening new avenues for reaction control.
• The study elucidates dissociation channels and control mechanisms, paving the way for advanced light-induced chemistry.