Dissociative Electron Attachment to 2,3,6,7,10,11-Hexabromotriphenylene

Area of Science:

• Physical Chemistry
• Chemical Physics
• Materials Science

Background:

• Polycyclic aromatic hydrocarbons (PAHs) and their halogenated derivatives are crucial in materials science.
• Understanding electron interactions with these molecules is key to predicting their electronic properties and reactivity.
• Brominated triphenylenes represent a class of PAHs with potential applications influenced by their electronic structure.

Purpose of the Study:

• To investigate the electron attachment processes of 2,3,6,7,10,11-Hexabromotriphenylene (HBTP) and 2,3,6,7,10-pentabromotriphenylene (PBTP).
• To determine the decay channels of transient molecular negative ions formed upon electron attachment.
• To measure the electron affinities and autodetachment lifetimes of these brominated triphenylenes.

Main Methods:

• Dissociative Electron Attachment Spectroscopy (DEAS) was employed to study HBTP and PBTP.
• Resonance energies and decay pathways were analyzed.
• An Arrhenius approach was used to evaluate adiabatic electron affinities.
• Density Functional Theory (DFT) calculations provided theoretical benchmarks.

Main Results:

• The dominant decay channel observed was the elimination of bromide ions (Br⁻).
• Resonances were identified in the low electron energy region, indicating specific interaction energies.
• Long-lived parent anions were formed with an autodetachment lifetime (τa) of 310 μs at thermal electron energies.
• Adiabatic electron affinities (EAa) were determined to be 1.12 ± 0.1 eV for HBTP and 1.09 ± 0.1 eV for PBTP.

Conclusions:

• DEAS is effective in elucidating the electron interaction mechanisms of brominated triphenylenes.
• The study provides crucial data on the stability and electronic properties of HBTP and PBTP negative ions.
• Experimental findings are in good agreement with DFT predictions, validating the computational approach.