Effect of Incremental Hydration on Reverse Internal Conversion Vibrational Autodetachment of an Anion

Area of Science:

• Physical Chemistry
• Chemical Physics
• Molecular Dynamics

Background:

• The mechanism of reverse internal conversion vibrational autodetachment (RICVAD) involves electron emission from hot ground state anions.
• This process is typically mediated by the statistical population of a dipole-bound state in isolated anions.

Purpose of the Study:

• To investigate the influence of water molecules on the RICVAD mechanism in nitrobenzene radical anions (NB⁻).
• To understand how hydration affects electron emission dynamics and potential new decay channels.

Main Methods:

• Anion photoelectron imaging was used to study nitrobenzene radical anion clusters with up to two water molecules (NB⁻(H₂O)₁ and NB⁻(H₂O)₂).
• Photoexcitation energies were varied to probe different electronic states and decay pathways.

Main Results:

• RICVAD was observed to be active in NB⁻(H₂O)₁, indicating the mechanism's robustness.
• An additional decay channel involving cluster dissociation and subsequent RICVAD of isolated NB⁻ was identified at higher energies for NB⁻(H₂O)₁.
• RICVAD signatures were present but obscured by other signals in NB⁻(H₂O)₂.

Conclusions:

• The RICVAD mechanism remains viable in the presence of hydrating water molecules.
• Hydration influences the resonance dynamics of anions and can lead to new dissociation pathways.
• The study highlights the impact of a complex chemical environment on fundamental electron emission processes.