THE UV-VIS SPECTRUM OF ClSO RADICAL FROM THE PHOTOLYSIS of THIONYL CHLORIDE AT 248 nm

Chao, Wen

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https://hdl.handle.net/2142/122487 Copy

Description

Title

THE UV-VIS SPECTRUM OF ClSO RADICAL FROM THE PHOTOLYSIS of THIONYL CHLORIDE AT 248 nm

Author(s)

Chao, Wen

Contributor(s)

• Winiberg, Frank A. F.
• Percival, Carl J.
• Okumura, Mitchio
• Jones, Gregory H

Issue Date

2023-06-20

Keyword(s)

Radicals

Abstract

Sulfinyl radicals (R-SO) play a critical role in various fields, from biology to atmospheric chemistry, such as aerosol formation in which chlorine atoms were proposed to potentially catalyze the oxidation of sulfur species in Venus’ atmosphere. In this study, we performed a Pulsed Laser Photolysis experiment to detect ClSO from Cl₂SO photolysis at 248 nm in a gas flow reactor using time-resolved UV-Vis transient absorption spectroscopy. A strong absorption near 303 nm and a weak one around 385 nm, with a vibrational progression of about 658 cm⁻¹ and 227 cm⁻¹, was recorded. Ab initio calculations at the EOMEE-CCSD/ano-pVQZ level revealed that the strong and weak band corresponds to the 1²A” ← X²A” and the 2²A’ ← X²A” transitions. Further analysis showed that there might be a conical intersection between the 1²A’ and 2²A’ state near the ground-state geometry, which poses a challenge for further theoretical work. Furthermore, we constructed a molecular orbital diagram analysis to understand the electronic structure of the sulfinyl functional group. The analysis suggested that sulfinyl radicals tend to form chemical bonds with other radicals. As an example, a fast recombination rate coefficient of Cl + ClSO → Cl₂SO reaction was investigated to be kCl₊ClSO = (1.48 ± 0.42)×10⁻¹¹ cm³ molecule⁻¹ s⁻¹ at 292 K and 90 Torr utilizing the strong absorption band. These results suggest that the Cl-containing SOₓ species might act as radical reservoirs in sulfur oxide-rich environments such as Venus’ atmosphere.

Publisher

International Symposium on Molecular Spectroscopy

Type of Resource

Text

Language

eng

Handle URL

https://hdl.handle.net/2142/122487

DOI

https://doi.org/10.15278/isms.2023.6813

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