Origin of the low energy resonance in the double photoionization of pyrene and coronene, and its absence in the double photoionization of corannulene

TL;DR

This study uses a Hubbard model approach to analyze the origin of low energy resonances in double photoionization of certain aromatic hydrocarbons, revealing their association with interior carbon atoms and explaining their absence in corannulene.

Contribution

It introduces a theoretical explanation linking low energy resonances to interior carbon atoms and explains their absence in corannulene based on atom count.

Findings

Low energy resonances are linked to interior carbon atoms in pyrene and coronene.

No low energy resonance is observed in corannulene with an odd number of interior carbons.

The approach clarifies the structural factors influencing photoionization resonances.

Abstract

The low energy resonance in the double photoionization of the aromatic hydrocarbons pyrene (C$_{16}$H$_{10}$) and coronene (C$_{24}$H$_{12}$) is investigated theoretically using an approach based on the one-dimension Hubbard model for $\pi$-conjugated systems with nearest-neighbor interactions. The Independent Subsystem Approximation, where the perimeter and interior carbon atoms are treated as independent entities, is employed. Since no low energy resonances have been found in aromatic hydrocarbons where there are only perimeter carbon atoms, we attribute the low energy resonances in pyrene and coronene to the interior carbon atoms. However, corannulene (C$_{20}$H$_{10}$) having five interior carbon atoms does not exhibit a low-energy resonance in the experimental data. We attribute the absence of this resonance to the odd number of interior carbon atoms.