University of Illinois Urbana-Champaign

Ozone Photodissociation In The Singlet Channel At 226 Nm

Aardema, Megan

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WH03_1.pptx
6350.pdf

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https://hdl.handle.net/2142/116804

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Title
Ozone Photodissociation In The Singlet Channel At 226 Nm
Author(s)
Aardema, Megan
Contributor(s)
  • North, Simon
  • McBane, George
Issue Date
2022-06-22
Keyword(s)
Mini-symposium: Spectroscopy meets Chemical Dynamics
Abstract
Ozone photodissociation plays an important role in atmospheric chemistry and has been the focus of many experimental and theoretical studies. In the Hartley band (200-300 nm) there are two spin-allowed dissociation channels, one forming excited state, singlet products (O2(a 1$\Delta$g) + O(1D)), and one forming ground state, triplet products (O2(X 3$\Sigma$g-) + O(3P)). The singlet channel is the primary dissociation channel in the Hartley band, and numerous studies have characterized the dissociation at longer wavelengths within the Hartley band. There has been considerable interest in the triplet channel dissociation at 226 nm following the observation of low velocity O(3P) fragments, but the singlet channel dissociation dynamics at 226 nm has not been previously reported. We report the rotational state distribution and vector correlations of the O2(a 1$\Delta$g, v=0) fragments arising from the 226 nm photodissociation of jet-cooled O3. Consistent with previously reported trends, the rotational distribution is shifted to higher rotational states with decreasing wavelength. We observe highly suppressed odd rotational state populations due to a strong $\Lambda$-doublet propensity. The measured rotational distribution is in agreement with classical trajectory calculations for the v=0 products, although the distribution is narrower than predicted. The spatial anisotropy follows the previously observed trend of decreasing $\beta$ with increasing photon energy with $\beta$ = 0.72 $\pm$ 0.14 for v=0, j=38. As expected for a triatomic molecule, the v-j correlation is consistent with v perpendicular to j, but the measured correlation is non-limiting due to rotational and translational depolarization. The j-dependent linewidth of the O2(a 1$\Delta$g) REMPI spectrum is also discussed in connection with the lifetime of the resonant O2(d 1$\Pi$g) state and predissociation via the II 1$\Pi$g valence state.
Publisher
International Symposium on Molecular Spectroscopy
Type of Resource
text
Genre of Resource
Conference Paper / Presentation
Language
eng
Handle URL
https://hdl.handle.net/2142/116804
DOI
https://doi.org/10.15278/isms.2022.WH03
Copyright and License Information
Copyright 2022 held by the authors

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Abstracts & Presentations - 2022 International Symposium on Molecular Spectroscopy PRIMARY