Anionic states of C₆Cl₆ probed in electron transfer experiments

Area of Science:

• Atomic and Molecular Physics
• Chemical Physics
• Surface Science

Background:

• Investigating electron transfer processes in molecule-atom collisions is crucial for understanding chemical dynamics.
• Hexachlorobenzene (C6Cl6) is a molecule of interest due to its electronic properties and potential environmental impact.

Purpose of the Study:

• To comprehensively study the anionic species formed during collisions of potassium atoms with hexachlorobenzene.
• To determine the vertical electron affinity of hexachlorobenzene and analyze its electronic states involved in ion-pair formation.

Main Methods:

• Utilized ion-pair formation experiments involving fast neutral potassium (K) atom collisions with neutral hexachlorobenzene (C6Cl6) molecules.
• Employed time-of-flight mass spectrometry to record anion yields across a wide collision energy range (10-100 eV).
• Integrated state-of-the-art theoretical calculations to analyze the electronic structure and molecular orbitals involved.

Main Results:

• Determined a vertical electron affinity of (-3.76 ± 0.20) eV for hexachlorobenzene, linked to Cl- formation.
• Identified that over 80% of the total anion yield consists of undissociated parent anions (C6Cl6-, C6Cl5-) and Cl-.
• Observed fragment anions (e.g., C6Cl4-, C2Cl-) constituting less than 20% of the total yield.

Conclusions:

• Provided the most comprehensive assignments of hexachlorobenzene anionic species to date.
• Elucidated the role of C6Cl6 electronic states in collision-induced dissociation.
• Demonstrated the synergy of experimental and theoretical approaches in electron transfer studies.