Spectroscopic and Kinetic Studies of the ClSO Radical from Cl2SO Photolysis.
J Am Chem Soc
; 144(44): 20323-20331, 2022 11 09.
Article
em En
| MEDLINE
| ID: mdl-36301796
ABSTRACT
Thionyl chloride (Cl2SO) serves as a common Cl atom source in widespread applications of chlorine chemistry though little is known about the reactivity and spectroscopy of the ClSO radical after a Cl-S bond cleavage. We performed a Pulsed Laser Photolysis experiment to detect ClSO from Cl2SO photolysis at 248 nm in a gas-flow reactor by time-resolved UV-vis transient absorption spectroscopy. A few chemical tests, using I2 and NO2, suggested the structured absorption band between 260 and 320 nm belonged to ClSO radical and that the termolecular ClSO + Cl + M â Cl2SO association reaction occurred. From EOMIP-CCSD/ano-pVQZ calculations, the ClSO band was assigned to the 12Aâ³ â X2Aâ³ transition involving the π* â π transition of the SO bond and the vibrational progression to the SO stretching mode of the 12Aâ³ state, with a maximum cross-section = (2.0 ± 0.5) × 10-18 cm2 near 286 nm (1σ uncertainty) and an average spacing of vibrational structure of 658 cm-1. The rapid decay of the ClSO signal monitored near 303 nm could be fit to a second-order kinetic model over 10-90 Torr, which yields an effective bimolecular rate coefficient kCl+ClSO = (1.48 ± 0.42) × 10-11 cm3 molecule-1 s-1 at 292 K and 90 Torr (1σ uncertainty). This fast recombination reaction suggests that Cl-containing SOx species might act as significant Cl atom reservoirs in sulfur oxide-rich environments such as Venus' atmosphere. Moreover, the reported UV spectrum provides a new means for monitoring the ClSO radicals.
Texto completo:
1
Base de dados:
MEDLINE
Assunto principal:
Atmosfera
/
Cloro
Idioma:
En
Ano de publicação:
2022
Tipo de documento:
Article