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Preparation of a Corannulene-functionalized Hexahelicene by Copper(I)-catalyzed Alkyne-azide Cycloaddition of Nonplanar Polyaromatic Units
Published on: September 18, 2016
Dissociation and multiple ionization energies for five polycyclic aromatic hydrocarbon molecules
A I S Holm1, H A B Johansson, H Cederquist
1Department of Physics, Stockholm University, SE-106 91 Stockholm, Sweden.
The Journal of Chemical Physics
|February 2, 2011
Summary
Polycyclic aromatic hydrocarbons (PAHs) were studied computationally. Their stability and fragmentation were analyzed, revealing charge-dependent behaviors crucial for understanding interstellar chemistry.
Area of Science:
- Astrochemistry and Computational Chemistry
- Physical Chemistry of Polycyclic Aromatic Hydrocarbons (PAHs)
Background:
- Polycyclic aromatic hydrocarbons (PAHs) are abundant molecules in interstellar space.
- Understanding their ionization and fragmentation is key to interpreting astronomical observations.
Purpose of the Study:
- To investigate the ionization energies and fragmentation pathways of PAHs under various charge states.
- To determine the thermodynamic stability of charged PAHs and their potential survival in space.
Main Methods:
- Density functional theory (DFT) calculations were employed.
- Calculations covered neutral and multiply charged PAHs (naphthalene, biphenylene, anthracene, pyrene, coronene).
- Analysis included adiabatic/vertical ionization energies, dissociation energies, and reaction barriers.
Main Results:
- Linear dependencies observed between ionization energies and charge states for all studied PAHs.
- Distinct size dependencies in ionization and fragmentation cross sections for pericondensed vs. catacondensed PAHs.
- PAHs exhibit thermodynamic stability up to specific charge states (e.g., q=2 for naphthalene, q=4 for coronene).
Conclusions:
- Charged PAHs can be stable beyond thermodynamic limits due to kinetic barriers.
- Findings provide insights into the survival and evolution of PAHs in interstellar environments.
- The study offers a foundation for interpreting spectral data from astronomical sources.
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