Laser-controlled dissociation of C2H2(2+): Ehrenfest dynamics using time-dependent density functional theory

Area of Science:

• Chemical Physics
• Quantum Chemistry
• Laser-Induced Dynamics

Background:

• Acetylene dication (C(2)H(2)(2+)) is a challenging molecular system.
• Understanding molecular dissociation under intense laser fields is crucial for chemistry and physics.

Purpose of the Study:

• To investigate the dissociation pathways of acetylene dication under intense laser fields.
• To explore the influence of laser frequency and polarization on fragmentation patterns.

Main Methods:

• Ab initio Ehrenfest dynamics simulations.
• Time-dependent density functional theory (TDDFT).
• Application of various laser field frequencies (9.5–13.6 eV) and directions.

Main Results:

• Four fragmentation channels observed with perpendicular fields at high frequencies.
• Fragmentation occurs at all frequencies with parallel fields.
• C-H bond breakage increases with laser frequency for parallel fields.
• Selective dissociation patterns achieved with low-frequency parallel fields.

Conclusions:

• Laser field parameters (frequency, direction) enable control over acetylene dication dissociation.
• Ehrenfest dynamics and TDDFT provide insights into laser-matter interactions.
• Potential energy surface analysis rationalizes observed fragmentation.