Bond-selective dissociation of polyatomic cations in mid-infrared strong fields

Area of Science:

• Physical Chemistry
• Quantum Mechanics
• Molecular Dynamics

Background:

• Controlling molecular dissociation is crucial for chemical synthesis and understanding reaction mechanisms.
• Selective bond cleavage in molecular ions presents unique challenges due to their charge and stability.

Purpose of the Study:

• To investigate strong field-induced dissociation in molecular cations using intense mid-infrared laser pulses.
• To demonstrate bond-selective fragmentation in bromofluoroform monocation (CF3Br(+)) and iodobenzene dication (C6H5I(2+)).

Main Methods:

• Utilized ab initio molecular dynamics calculations to simulate laser-matter interactions.
• Employed intense mid-infrared laser pulses with controlled polarizations and wavelengths.
• Analyzed dissociation pathways and branching ratios for different molecular systems.

Main Results:

• Achieved bond-selective dissociation in both CF3Br(+) and C6H5I(2+) by tuning laser parameters.
• Enhanced fluorine elimination in CF3Br(+) using specific wavelengths (7-8 μm) and C-F bond polarization.
• Demonstrated control over hydrogen elimination sites in C6H5I(2+) by altering laser polarization.

Conclusions:

• Strong mid-infrared fields offer a versatile tool for achieving bond-selective dissociation in molecular cations.
• Laser polarization and wavelength are key parameters for controlling fragmentation pathways.
• The findings highlight the general applicability of this technique for targeted molecular dissociation.