Rydberg spectra of singlet metastable states of O₂

Abstract

Updated analyses of several singlet Rydberg states of O₂ via spectra involving excitation from the metastable a¹Δ_g and ${\text{b}}^1{\mathrm{\Sigma }}_{\text{g}}^{+}$ states are presented. The high-quality FT-VUV spectra available from the DESIRS beamline at the SOLEIL synchrotron gives significantly improved spectra compared to previous work. The Rydberg states analysed include $3\text{p}{\pi }^1{\mathrm{\Sigma }}_{\text{u}}^{+}$ v = 0–4, 3pσ¹Π_u v = 0–2, 3pπ¹Δ_u v = 0–2, $4\text{p}{\pi }^1{\mathrm{\Sigma }}_{\text{u}}^{+}$ v = 0–1, 4pσ¹Π_u v = 0 and 4pπ¹Δ_u v = 0. This is complemented by high-quality ab initio calculations on the ${}^1{\mathrm{\Sigma }}_{\text{u}}^{+}$ and ¹Δ_u Rydberg states to determine the transition moments providing the first quantitative cross-sections for Rydberg – ${\text{b}}^1{\mathrm{\Sigma }}_{\text{g}}^{+}$ transitions. These are validated against the experimental data. The results suggest the most promising candidate for determining ${\text{b}}^1{\mathrm{\Sigma }}_{\text{g}}^{+}$ number density is likely to be the 1–0 band of the $4\text{p}{\pi }^1{\mathrm{\Sigma }}_{\text{u}}^{+}-{\text{b}}^1{\mathrm{\Sigma }}_{\text{g}}^{+}$ transition at 131.3 nm.

GRAPHICAL ABSTRACT

KEYWORDS:

• Spectroscopy
• Rydberg states
• oxygen
• metastable states
• vacuum ultraviolet

Acknowledgements

This research was performed within the LABEX Plas@par project, and received financial state aid managed by the Agence Nationale de la Recherche, as part of the programme ‘Investissements d’avenir’ under the reference ANR-11-IDEX-0004-02.

Disclosure statement

No potential conflict of interest was reported by the author(s).

Additional information

Funding

This work was supported by Agence Nationale de la Recherche [grant number ANR-11-IDEX-0004-02].