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Dissociative electron attachment to carbon tetrachloride probed by velocity map imaging
Anirban Paul1, Dhananjay Nandi1,2, Daniel S Slaughter3
1Indian Institute of Science Education and Research Kolkata, Mohanpur 741246, India.
Physical Chemistry Chemical Physics : PCCP
|January 17, 2024
Summary
Investigating carbon tetrachloride (CCl4) bond-breaking via dissociative electron attachment (DEA) reveals complex dynamics. Specific electron resonances trigger unique fragmentations and angular distributions, indicating advanced molecular interactions.
Area of Science:
- Chemical Physics
- Molecular Dynamics
- Quantum Chemistry
Background:
- Dissociative electron attachment (DEA) is a key process in molecular fragmentation.
- Understanding bond-breaking mechanisms in halogenated compounds like carbon tetrachloride (CCl4) is crucial for chemical physics.
- Previous models struggled to explain complex dissociation pathways in CCl4.
Purpose of the Study:
- To investigate the bond-breaking dynamics of CCl4 using dissociative electron attachment.
- To elucidate the influence of electron resonances on fragmentation patterns and angular distributions.
- To explore novel mechanisms beyond single-electronic-state models.
Main Methods:
- Utilizing a velocity map imaging (VMI) spectrometer to study DEA in CCl4.
- Analyzing fragment anion (Cl-, Cl2-, CCl2-) production and kinetic energies.
- Examining angular distributions of fragments to infer dissociation dynamics.
Main Results:
- Near-zero eV electron attachment shows efficient intramolecular vibrational redistribution, with low fragment translational energy.
- A 6.2 eV resonance produces fast Cl2- fragments with a forward-peaking angular distribution, suggesting Jahn-Teller distortion and bending dynamics.
- CCl2- fragments exhibit a backward-peaking angular distribution, indicative of long-distance electron hopping.
Conclusions:
- The study reveals complex dissociation dynamics in CCl4 beyond simple models.
- Jahn-Teller distortions and electron hopping mechanisms play significant roles in specific DEA channels.
- VMI spectroscopy provides detailed insights into molecular fragmentation pathways.
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