Fragmentation dynamics in dissociative electron attachment to CO probed by velocity slice imaging

Area of Science:

• Chemical Physics
• Molecular Dynamics
• Quantum Chemistry

Background:

• Dissociative electron attachment (DEA) is a fundamental process in molecular physics.
• Understanding DEA dynamics is crucial for fields like plasma chemistry and atmospheric science.
• Carbon monoxide (CO) is a simple, yet important, diatomic molecule with complex electron interaction dynamics.

Purpose of the Study:

• To investigate the complete dissociation dynamics of electron attachment to CO molecules.
• To elucidate the specific pathways and resonant states involved in O(-) ion formation.
• To analyze the kinetic energy and angular distributions of O(-) ions.

Main Methods:

• Utilized the velocity slice imaging (VSI) technique for high-resolution measurements.
• Studied electron attachment at incident electron energies from 9 to 11.5 eV.
• Analyzed kinetic energy and angular distributions of O(-) ions.

Main Results:

• Identified two distinct DEA reactions forming O(-) ions.
• Determined that these reactions lead to neutral C atoms in either the ground (3P) or excited (1D) states.
• Angular distributions indicated specific resonant states and interference between partial waves.

Conclusions:

• The study confirms two separate DEA pathways for O(-) formation from CO.
• Different resonant states, and potentially multiple intermediate states, are involved in each pathway.
• Interference effects between partial waves explain the observed forward-backward asymmetry in ion distributions.