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Computation of Atmospheric Concentrations of Molecular Clusters from ab initio Thermochemistry
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Formation of Hydrogen Peroxide from O-(H2O) Clusters
1Division of Applied Chemistry, Faculty of Engineering, Hokkaido University, Sapporo 060-8628, Japan.
The Journal of Physical Chemistry. A
|May 25, 2021
Summary
Hydrogen peroxide (H2O2) is formed from oxygen radical anions and water clusters. Direct ab initio molecular dynamics calculations show H2O2 forms rapidly via photoelectron detachment, especially in smaller clusters.
Area of Science:
- Physical Chemistry
- Quantum Chemistry
- Computational Chemistry
Background:
- Hydrogen peroxide (H2O2) is recognized as a clean energy carrier.
- Understanding the formation mechanisms of H2O2 is crucial for its application.
- Oxygen radical anions interacting with water clusters are potential precursors.
Purpose of the Study:
- To investigate the direct formation of H2O2 from O-(H2O)n clusters.
- To elucidate the reaction mechanism and dynamics of H2O2 synthesis.
- To compare the influence of different electronic states of oxygen atoms on H2O2 formation.
Main Methods:
- Direct ab initio molecular dynamics (AIMD) calculations were employed.
- Simulations covered oxygen radical anion water clusters (n=1-6).
- Three electronic states of oxygen (3P, 1D, 1S) were examined.
Main Results:
- H2O2 is formed via photoelectron detachment of O-(H2O)n clusters, primarily through the O(1S) state.
- Intracluster reactions involving hydrogen atom transfer lead to H2O2 formation within 100 fs for n=1.
- Larger cluster sizes (n=2-6) showed slower reaction times (80-180 fs).
- Dissociation, rather than H2O2 formation, occurred for O(3P) and O(1D) states.
Conclusions:
- The O(1S) electronic state is essential for the direct formation of H2O2 from O-(H2O)n clusters.
- The reaction mechanism is consistent across different cluster sizes, with kinetics dependent on size.
- AIMD simulations provide valuable insights into the ultrafast dynamics of H2O2 synthesis.
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