Single-Photon Double Ionization of Ozone

TL;DR

This study presents the first experimental and theoretical analysis of valence double photoionization in ozone, revealing complex fragmentation dynamics and excited atomic oxygen fragments.

Contribution

It introduces new experimental data and high-accuracy theoretical mapping of ozone's double ionization and dissociation pathways.

Findings

First single-photon valence double ionization electron spectrum of O3

Dissociative double ionization produces excited atomic oxygen fragments

Reveals richer fragmentation dynamics than previously known

Abstract

Ozone (O3) is a triatomic molecule of central importance in the chemistry and physics of the Earth's and other planetary atmospheres. Beyond its environmental significance, a detailed understanding of the electronic structure and ionization dynamics of ozone is essential for modeling atmospheric, ionospheric, and astrochemical processes. In the present work, we substantially extend the experimental and theoretical characterization of ozone into the regime of valence double photoionization. Using HeII-alpha, HeII-beta, and higher-energy vacuum ultraviolet radiation in combination with a versatile multiple charged-particle correlation detection technique, we report the first single-photon valence double ionization electron spectrum of O3. To interpret the experimental observations, we mapped the lowest potential energy surfaces of dicationic ozone employing post-Hartree-Fock multi-configurational-interaction methods, and computed with high accuracy the energetics of the relevant dissociation channels. Our results demonstrate that dissociative double ionization of ozone produces electronically excited cationic atomic oxygen fragments in addition to the ground-state dissociation pathway, revealing a richer fragmentation dynamics than hitherto recognized.