Stepwise Activation of Water by Open-Shell Interactions, Cl(H₂O)

Area of Science:

• Physical Chemistry
• Computational Chemistry
• Chemical Physics

Background:

• Investigates the chemical activation of water by single chlorine atoms.
• Builds upon prior analysis of chlorine radical-water interactions for small clusters (n=1-4).

Purpose of the Study:

• To computationally examine chlorine radical-water clusters (Cl·(H2O)n) near the onset of ion hydration.
• To explore structural, electronic, and vibrational properties of different isomer classes.

Main Methods:

• Computationally surveyed thousands of unique isomers for chlorine-water clusters.
• Analyzed electronic structures and harmonic vibrational frequencies.
• Investigated three main structural classes: intact hydrated chlorine, hydrogen-transferred, and charge-transferred configurations.

Main Results:

• Identified three distinct structural classes of isomers: intact, hydrogen-transferred, and charge-transferred.
• Charge-transferred isomers significantly stabilized with increased hydration, energetically approaching hydrogen-transferred forms.
• Observed that hydration levels studied were insufficient to achieve energetic crossover between intact complexes and charge-separated configurations.

Conclusions:

• Internal hydration of ions is likely required for complete charge separation in these systems.
• Complete charge separation is anticipated to occur at larger cluster sizes.
• Provides experimentally verifiable computational predictions for vibrational signatures.